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I have a visual studio solution.
I have many projects in the solution.
There is one main project which acts as the start up and uses other projects.
There is one project say "ProjectX". Its reference is added to main project.
The ProjectX references another .NET dll (say abc.dll) that isn't part of the solution.
Now this abc.dll should be copied to bin/debug folder of main project, but it isn't getting copied there. Why is it not getting copied, any known reasons ?
I found that if ProjectX referenced the abc.dll but didn't directly use any of the types DEFINED in abc.dll, then abc.dll would NOT be copied to the main output folder. (It would be copied to the ProjectX output folder, to make it extra-confusing.)
So, if you're not explicitly using any of the types from abc.dll anywhere in ProjectX, then put a dummy declaration somewhere in one of the files in ProjectX.
AbcDll.AnyClass dummy006; // this will be enough to cause the DLL to be copied
You don't need to do this for every class -- just once will be enough to make the DLL copy and everything work as expected.
Addendum: Note that this may work for debug mode, but NOT for release. See #nvirth's answer for details.
Just a sidenote to Overlord Zurg's answer.
I've added the dummy reference this way, and it worked in Debug mode:
public class DummyClass
{
private static void Dummy()
{
var dummy = typeof(AbcDll.AnyClass);
}
}
But in Release mode, the dependent dll still did not get copied.
This worked however:
public class DummyClass
{
private static void Dummy()
{
Action<Type> noop = _ => {};
var dummy = typeof(AbcDll.AnyClass);
noop(dummy);
}
}
This infomation actually costed me hours to figure out, so I thought I share it.
Yes, you'll need to set Copy Local to true. However, I'm pretty sure you'll also need to reference that assembly from the main project and set Copy Local to true as well - it doesn't just get copied from a dependent assembly.
You can get to the Copy Local property by clicking on the assembly under References and pressing F4.
It looks slick when you make it an assembly attribute
[AttributeUsage(AttributeTargets.Assembly)]
public class ForceAssemblyReference: Attribute
{
public ForceAssemblyReference(Type forcedType)
{
//not sure if these two lines are required since
//the type is passed to constructor as parameter,
//thus effectively being used
Action<Type> noop = _ => { };
noop(forcedType);
}
}
The usage will be:
[assembly: ForceAssemblyReference(typeof(AbcDll.AnyClass))]
Ran into this same issue. Background info: before building, I had added a new Project X to the solution. Project Y depended on Project X and Project A, B, C depended on Project Y.
Build errors were that Project A, B, C, Y, and X dlls could not be found.
Root cause was that newly created Project X targeted .NET 4.5 while the rest of the solution projects targeted .NET 4.5.1. Project X didn't build causing the rest of the Projects to not build either.
Make sure any newly added Projects target the same .NET version as the rest of the solution.
Not sure if this helps but for me, many times I reference a DLL (which automatically adds it to the bin folder of course). However that DLL might need additional DLLs (depending on what functions I'm using). I do NOT want to reference those in my Project because they just simply need to end up in the same folder as the DLL I am actually using.
I accomplish this in Visual Studio by "Adding an existing file". You should be able to add it anywhere except the Add_data folder. personally I just add it to the root.
Then change the properties of that file to ...
Build Action = None (having this set to something like Content actually copies the "root" version to the root, plus a copy in the Bin).
Copy to output folder = Copy if Newer (Basically puts it in the BIN folder only if it is missing, but doesn't do it after that)
When I publish.. my added DLL's only exists in the BIN folder and nowhere else in the Publish location (which is what I want).
You could also check to make sure the DLLs you're looking for aren't included in the GAC. I believe Visual Studio is being smart about not copying those files if it already exists in the GAC on the build machine.
I recently ran in this situation where I'd been testing an SSIS package that needed assemblies to exist in the GAC. I'd since forgotten that and was wondering why those DLLs weren't coming out during a build.
To check what's in the GAC (from a Visual Studio Developer Command Prompt):
gacutil -l
Or output to a file to make it easier to read:
gacutil -l > output.txt
notepad.exe output.txt
To remove an assembly:
gacutil -u MyProjectAssemblyName
I should also note, that once I removed the files from the GAC they were correctly output in the \bin directory after a build (Even for assemblies that were not directly referenced in the root project). This was on Visual Studio 2013 Update 5.
If you right Click the referenced assembly, you will see a property called Copy Local. If Copy Local is set to true, then the assembly should be included in the bin. However, there seams to be a problem with Visual studio, that sometimes it does not include the referenced dll in the bin folder... this is the workaround that worked for me:
In my case, it was the stupidest thing, caused by a default behavior of TFS/VS that I disagree with.
Since adding the dll as a reference to the main project did not work, I decided to add it as an "Existing Item", with Copy Local = Always. Even then the file was not there.
Turns out that, even though the file is present on the VS Solution and everything compiled both locally and on the server, VS/TFS did not add actually add the file to source control. It was not included on the "Pending Changes" at all. I had to manually go to the Source Control Explorer and explicitly click on the "Add items to folder" icon.
Stupid because I've been developing for 15 years in VS. I've run into this before, I just did not remember and somehow I missed it because everything still compiled because of the file being a regular reference, but the file that was added as Existing Item was not being copied because it did not exist on the source control server.
I hope this saves someone some time, since I lost 2 days of my life to this.
Issue:
Encountered with a similar issue for a NuGet package DLL (Newtonsoft.json.dll) where the build output doesn't include the referenced DLL. But the compilation goes thru fine.
Fix:
Go through your projects in a text editor and look for references with "Private" tags in them. Like True or False. “Private” is a synonym for “Copy Local.” Somewhere in the actions, MSBuild is taking to locate dependencies, it’s finding your dependency somewhere else and deciding not to copy it.
So, go through each .csproj/.vbproj file and remove the tags manually. Rebuild, and everything works in both Visual Studio and MSBuild. Once you’ve got that working, you can go back in and update the to where you think they need to be.
Reference:
https://www.paraesthesia.com/archive/2008/02/13/what-to-do-if-copy-local-works-in-vs-but.aspx/
Make sure that the dependent DLL used by you does not have target .NET Framework higher than the target .NET framework of your project's Application.
You can check this by selecting your project, then press ALT+ENTER, then select Application from left side and then select Target Framework of your project.
Suppose,
dependent DLL Target Framework = 4.0 and
Application DLL Target Framework = 3.5 then change this to 4.0
Thank you!
This is a slight tweak on nvirth's example
internal class DummyClass
{
private static void Dummy()
{
Noop(typeof(AbcDll.AnyClass));
}
private static void Noop(Type _) { }
}
I would do add it to Postbuild events to copy necessary libraries to the output directories. Something like XCopy pathtolibraries targetdirectory
You can find them on project properties -> Build Events.
TLDR; Visual Studio 2019 may simply need a restart.
I encountered this situation using projects based on Microsoft.NET.Sdk project.
<Project Sdk="Microsoft.NET.Sdk">
Specifically:
Project1: targets .netstandard2.1
references Microsoft.Extensions.Logging.Console via Nuget
Project2: targets .netstandard2.1
references Project1 via a Project reference
Project2Tests: targets .netcoreapp3.1
references Project2 via a Project reference
At test execution, I received the error messaging indicating that Microsoft.Extensions.Logging.Console could not be found, and it was indeed not in the output directory.
I decided to work around the issue by adding Microsoft.Extensions.Logging.Console to Project2, only to discover that Visual Studio's Nuget Manager did not list Microsoft.Extensions.Logging.Console as installed in Project1, despite it's presence in the Project1.csproj file.
A simple shut down and restart of Visual Studio resolved the problem without the need to add an extra reference. Perhaps this will save someone 45 minutes of lost productivity :-)
You may set both the main project and ProjectX's build output path to the same folder, then you can get all the dlls you need in that folder.
NO NEED FOR DUMMY IN CODE
Just :
add a Reference to the Executeable Project
or/and ensure that the reference in the executeable project has "Copy Local" set to TRUE (which was my "fault") is seems that this "overwrote" the setting in the base referenced library-project...
Other than the common ones above, I had a multi-project solution to publish. Apparently some files target different frameworks.
So my solution: Properties > Specific Version (False)
Add the DLL as an existing item to one of the projects and it should be sorted
VS2019 V16.6.3
For me the problem was somehow the main .proj file ended up with an entry like this for the project whose DLL wasn't getting copied to the parent project bin folder:
<ProjectReference Include="Project B.csproj">
<Project>{blah blah}</Project>
<Name>Project B</Name>
<Private>True</Private>
</ProjectReference>
I manually deleted the line <Private>True</Private> and the DLL was then copied to the main project bin folder on every build of the main project.
If you go to the reference of the problem project in the references folder of the main project, click it and view properties there is a "Copy Local" setting. The private tag equates to this setting, but for me for some reason changing copy local had no effect on the private tag in the .proj file.
Annoyingly I didn't change the copy local value for the reference, no idea how it got set that way and another day wasted tracking down a stupid problem with VS.
Thanks to all the other answers that helped zone me in on the cause.
HTH
I had a similar issue in which a DLL I had included in the project as content and 'Copy always' set, wasn't being copied to the bin folder. I solved this by adding a dependentAssembly reference to the DLL in the app.config.
So, as the title reads, I have a VS2010 solution with ~50 projects in it right now. If I make a change to a "top level" project that nothing references then VS still rebuilds all 50 projects. I'm running Visual Studio 2010 Ultimate without any add-ons. I am using ILMerge to consolidate all of the projects into a single file.
I have verified this by checking the time stamps of the lower level dlls and see that they are indeed rebuilt even though their code wasn't touched.
I've read all responses and comments for:
Visual Studio 2008 keeps rebuilding
Visual studio keeps building everything
Strange VS2010 build glitch occurs in my solution
Reasons for C# projects to rebuild in Visual Studio
But most of them just offer suggestions on unloading projects to speed up build times but nothing concrete as to a fix. I'm trying to figure out why VS thinks these dependent projects need to be rebuilt when they don't and fix it.
I've turned on 'Tools > Options > Projects and Solutions > Build and Run > Only build startup projects and dependencies on run' but with no effect.
Also, if I just rebuild a "mid-level" project that only has 8 (in)direct dependencies then it still builds all 8 projects even though ILMerge isn't invoked and none of the dependent projects have been modified.
Thank you everyone for any insight you may be able to provide.
Added
To test some of the suggestions I created a new WinForms project from scratch. I then created two new projects inside that solution. I copied all of the code and resources (not project file) from my two 'lowest level' projects into the two brand new projects (I did this by dropping the files and folders from Explorer onto the project in Visual Studio).
The lowest project, let's call it B, did not reference any other project. The next project, A, referenced B only. So once I added the required .NET and external assembly references to the projects then the solution would build.
I then had my new WinForm project reference A and did a full build. So the ref chain is:
WinForm -> A -> B
I then modified WinForm only and did a standard build (F6). As before, Visual Studio rebuilt all three projects.
After some systematic eleminiation of source files in project B I found that if I removed my Resources.Designer.cs and Resources.resx (and commented out the code that made use of the .Properties.Resources object of those resources) then a modification of WinForm would no longer rebuild the entire solution and would only rebuild WinForm.
Adding the Resources.resx and Resources.Designer.cs back to project B (but leaving the referenced code commented out so that nothing was making use of the resources) would re-introduce the full build behavior.
To see if perhaps my resource files were corrupted, I deleted them again and then created a new one (via Project Properties -> Resources) and re-added the same resource as before, which was a single Excel file. With this setup the full rebuild would still occur.
I then removed the single resource, but left the resource file in project B. Even with no resources added, but the resource file still in the project, the full (unneeded) rebuild would occur.
It appears that just having a resource file added to a (.NET 3.5) project will cause Visual Studio 2010 to always rebuild that project. Is this a bug or intended/expected behavior?
Thanks all again!
Open Tools - Options, select Projects and Solutions - Build and Run in tree, then set "MSBuild project build output verbosity" to Diagnostic.
This will output the reason for building a project, i.e.
Project 'ReferencedProject' is not up to date. Project item
'c:\some.xml' has 'Copy to Output Directory' attribute set to 'Copy
always'.
or
Project 'MyProject' is not up to date. Input file
'c:\ReferencedProject.dll' is modified after output file
'c:\MyProject.pdb'.
In this case the fix is to copy some.xml only if newer.
Pre and post build events can trigger build as well.
While I don't think this is a fix, it is a workaround that has worked for my situation...
I originally had about 5 projects out of 50 that contained a Resources section. These projects would always be rebuilt and thus anything that they depended on would also be rebuilt. One of those 5 projects was a "base" level library that 48 of the other projects referenced, thus 96% of my project would be rebuilt every time even if it didn't need it.
My workaround was to use dependency injection, interfaces, and a dedicated "Resources" project. Instead of having those 5 projects reference their own Resources object, I created an interface in each project that would supply the desired resources. Then, the classes that needed those resources would require that interface be passed in during their creation in the constructor (constructor injection).
I then created a separate "Resources" project that had an actual Resources section like normal. This project only contained the resources themselves, and a class for each interface that was needed to provide those resources via an interface. This project would reference every other project that had a resource dependency and implement the interface that the project needed.
Finally, in my "Top Level" project which nothing referenced (and where the exe was actually built and my composition root lives) I referenced the "Resources" project, wired up the DI, and away we went.
This means that only two projects (the "Resources" and the "Top Level") will be rebuilt every time, and if I do a partial build (Shift-F6) then they won't get rebuilt at all.
Again, not a great work around, but with 48 projects being built every time a build would take about 3 minutes, so I was losing 30 to 90 minutes a day with needless rebuilds. It took awhile to refactor, but I think it was a good investment.
Here is a simplified diagram. Note that the dependencies from Main.exe to Proj1 and Proj2 are not shown in order to reduce clutter.
With this design, I can do a build of Proj1 or Proj2 without triggering a full rebuild, since they don't have any dependencies on a Resources section. Only Main knows about the Resources implementation.
This happens when a project has a file that doesn't really exist.
The project can't determine if the file was changed (because it's not there) so it rebuilds.
Simply look at all the files in the project, and search for the one that doesn't have an expandable arrow near it.
I had the same issue in VS 2015.
What did the trick for me is:
One project was referencing itself copy in some other project bin (magic, yes). This kind of stuff could be found when switching to diagnostic build output (in build options) and then trying to build projects one by one from the top of projects hierarchy - if you see the project that rebuilds even if nothing has been changed then see it's references.
I've changed all "copy always" files in all projects to "copy if newer". Basically, in all .csproj files replace <CopyToOutputDirectory>Always</CopyToOutputDirectory>
to <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
Then I've disabled NTFS tunneling as described in this article with this powershell script:
New-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem" -Name "MaximumTunnelEntries" -Value 0 -PropertyType "DWord"
After that I needed on rebuild and it seems working for now.
In my case the culprit was "Copy Local" setting of a referenced dll set to true and "Copy to Output Directory" setting a file set to Copy always.
For .Net Core Projects, all solutions above are not working.
I've found the solution. In case you are using Visual Studio 2019:
Build the solution twice
Turn on Tools -> Options -> Projects and Solutions -> SDK-Style Projects -> Logging Level -> Verbose
Clear the output window
Build your start project
Inspect the output window. All the string starting with FastUpToDate
You will find some project items that are making your project not up to date.
Fix these issues and try again from step 1. If your fixes are correct, you will achieve Build: 0 succeeded, 0 failed, {n} up-to-date, 0 skipped in the last string of build output.
The MSBuild team is collecting documentation about investigating build incrementality issues here:
https://github.com/Microsoft/MSBuild/wiki/Rebuilding%20when%20nothing%20changed
UPDATED LINK: https://github.com/dotnet/msbuild/blob/main/documentation/wiki/Rebuilding-when-nothing-changed.md
Based on your observations, it sounds like you have projects expressing dependencies to other projects in a way that isn't obvious. It is possible for orphaned dependencies to remain in project files without being apparent in the UI. Have you looked through a misbehaving project file after opening it in a text editor? Checked solution build dependencies?
If you're not able to spot anything, try recreating one of your projects from scratch to see if the new project exhibits the same problem. If the clean project builds correctly, you'll know that you have unwanted dependencies expressed somewhere. As far as I know, these would have to be in the project file(s) or the solution file, unless you have makefiles or other unusual build steps.
Another problem that frequently happens is when some item in your solution has a modified stamp that is in the future. This can happen if you set your clock forward, and then set your clock to the correct time. I had this happen while installing Linux.
In this case you can recursively touch all the files using git bash (yes, in Windows):
find . -exec touch {} \;
I've finally found one more culprit that I had hard time finding by increasing the build log verbosity.
In some cases, MSBuild looks for vc120.pdb in the output folder, and if this file doesn't exist, it will rebuild the entire project. This occurs even if you have disabled debug symbol generation.
The workaround here is to enable debug symbols and let this file get generated, then disable the setting again without deleting the PDB file.
I had this same problem and it turned out to be related to a couple of project that had a copy local reference to a dll in their own output directory.
The key to finding this was having diagnostic output set for the build output, but also knowing what to look for in the log. Searching for: 'not up to date' was the key.
Here is an answer from VS2010 always rebuilds solution?
This issue is solved by changing the project files, cleaning solution,
deleting all bin folders by hand, restarting Visual studio and
rebuilding everything.
I had the same issues with you.
I found that it came from some deleted files.
When I had removed the files from my project, the issues was gone.
Regards.
For this category of build problems setting MSBuild output verbosity to 'diagnostic' is indeed a necessary first step. Most of the time the stated reason for the re-builds would be enough to act upon, BUT occasionally MSBuild would erroneously claim that some files are modified and need to be copied.
If that is the case, you'd need to either disable NTFS tunneling or duplicate your output folder to a new location. Here it is in more words.
I had the problem of Visual Studio rebuilding projects when upgrading from Visual Studio 2015 to 2017 and I add this answer for the benefit of those who might experience similar problems, as it does not seem to be documented anywhere.
In my case, the problem was that all projects in the solution had the same intermediate Output path (obj). The file GeneratedInternalTypeHelper.cs gets generated by all projects containing XAML. Up to Visual Studio 2015, the build process apparently did not check for the file date of this file and thus no problem with it occurred. With VS2017 the file date of this file is checked and because a later project in the build process will overwrite it (with the same content), the earlier project will re-build, re-triggering the later build, ad infinitum.
The solution in this case is to ensure that all projects have differing intermediate output directories, which will make the problem go away.
In my case (mixed C#, C++/CLI and native C++ solution) , some C++ projects were being re-linked even if nothing had changed. I spent ages trying to work out what was happening. In the end I worked out from the "Command Line" option that the PDB output path (option /Fd) could not handle the folder setting $(IntDir). I removed that - an empty value will do the default correctly - and my issue went away.
As others have noticed, a likely reason is that CopyToOutputDirectory is set to Always. This can be fixed simultaneously in all project files by applying the powershell script below:
$folder = "C:\My\Solution\Folder"
$csvFiles = Get-ChildItem $folder *.csproj -rec
foreach ($file in $csvFiles)
{
(Get-Content $file.PSPath -Encoding UTF8 -Raw) |
Foreach-Object { $_ -replace "<CopyToOutputDirectory>Always</CopyToOutputDirectory>", "<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>" } |
Set-Content $file.PSPath -Encoding UTF8 -NoNewline
}
Files that do not exist are a problem and obviously files producing no output as well. That can happen, wenn you have a resource file in a static library. (C++)
I just opened a solution from TFS using Visual Studio 2010. The solution contains more than 100 projects (if up to me, it would probably be less than 5) and many of them happen to miss a reference (to Unity dll's).
Is there any way to simplify the fixing of these references? Now I have to delete and re-add all of them manually. Hassle.
Any suggestions would be appreciated.
To fix the problem you need to find out from where it tries to load the files. You can do so looking in the project csproj file. You either have newer (or different) versions of the assemblys installed or you have a different file and folder structure. You need to recreate the file and folder structure that has been used in that project or rewrite the csproj file to the new location.
For the future you might want to change how 3rd party references are handled. I have good experiences using this approach: Define a ThirdPartyLibraries Folder where all those libraries go and check it in. It should be in the solution folder. Everybody has to put 3rd party libs in there from now on and use them instead.
Might want to check out resharper, it might do what you need for references. I know it helps optimize and identify references in classes, not sure at the project level. Resharper has a 30 day trial
You can add all those binaries in to Binaries folder and add in to your TFS.
Now add the binaries as existing item in your solution items, so that when you open the solution it fetches all the solution items as well.
Make sure the references are added from the binaries folder.
If the location of the referenced assembly has changed, then it is relative simple to do a Find and Replace in files on the .csproj files to replace the broken reference with the correct one.
Hereis the situation:
I have a folder that contains library DLLs, which are not built as part of my solution - lets say it is .\libs.
I add references to these DLLs. I then build. Everything is fine.
If I then delete the libs folder and rebuild my solution, the compilation still succeeds! Weird - I would have expected compilation errors since the library dlls are not there!
But looking at the reference properties in Visual studio, I see that the reference path has been changed from .\libs\foo.dll to myproject\bin\Debug\foo.dll. So it is picking up the referenced DLL from its old build output.
If I open myproject.csproj in a text editor, I see that the HintPath of the reference is still .\libs\foo.dll. If I re-create the libs folder, visual studio still uses myproject\bin\Debug\foo.dll (it does not revert to the actual DLL I want!)
Is this expected behaviour?
Is there a way to stop this behaviour because it is causing me problems - especially when I want to rebuild myproject with different versions of the libs: half the time I find that I am using a different version than what I wanted.
This is not magic. Your DLL's Copy Local Property is probably set to true, that's all.
Setting it to false will get you the desired behaviour.
This is driving me crazy.
I have a rather large project that I am trying to modify. I noticed earlier that when I typed DbCommand, visual studio did not do any syntax highlighting on it, and I am using using System.Data.Common.
Even though nothing was highlighted, the project seemed to be running fine in my browser. So I decided to run the debugger to see if things were really working as they should be.
Every time the class that didn't do the highlighting is called I get the "the source file is different from when the module was built" message.
I cleaned the solution and rebuilt it several times, deleted tmp files, followed all the directions here Getting "The source file is different from when the module was built.", restarted the web server and still it tells me the source files are different when they clearly are not.
I cannot test any of the code I have written today because of this.
How can the source be different than the binary when I just complied
it?
Is there any way to knock some sense into visual studio, or am
I just missing something?
I got this issue running a console app where the source that was different was the source that had the entry-point (static void Main). Deleting the bin and obj directories and doing a full rebuild seemed to correct this, but every time I made a code change, it would go out-of-date again.
The reason I found for this was:
I had checked "Only build startup projects and dependencies on Run" (Tools -> Options -> Projects and Solutions -> Build and Run)
In Configuration Manager, my start-up project didn't have "Build" checked
(For #2 -> accessible via the toolbar under the 'Debug/Release' drop down list.)
I was just having this same problem, my projects were all in the same solution so they were using Project to Project references, so as one changed the others should have been updated. However it was not the case, I tried to build, rebuild, close VS2010, pulled a new copy from our source control. None of this worked, what I finally ended up trying was right clicking on the project and rebuilding each project individually. That updated the .dlls and .pdb files so I could debug through.
The issue here is that your dll and or your pdb files are not in sync.
Follow these steps
Just delete the bin directory from the project where the DLL is generated.
Re-build the project.
Remove reference from the project that make reference to the DLL.
Include again the reference.
Enjoy.
In addition to these answers I had the same issue while replacing new DLLs with old ones because of the wrong path. If you are still getting this error you may not refer the wrong path for the DLLs. Go to IIS manager and click the website which uses your DLLs. On the right window click Advanced Settings and go to path of the Physical Path folder on File Explorer and be sure that you are using this folder to replace your DLLs.
Some things for you to check:
Have you double checked your project references?
Do you have a Visual Studio started web server still running? Check the system tray and look for a page with a cog icon (you may have more than one):
(source: msdn.com)
Right click and close/exit it. You may have more than one. Can you debug your changes now?
Are you running the debug version but have only built the release version (or vice versa)?
Did the compile actually succeed? I know I've clicked through the "there were errors, do you want to continue anyway?" message a couple of times without realising.
With web services, the problem can be caused by using the Visual Studio "View in Browser" command. This places the service's DLL and PDB files in the bin and obj folders. When stepping into the web service from a client, somehow Visual Studio uses the PDB in the bin (or obj) folder, but it uses the DLL in the project's output build folder. There are a couple workarounds:
Try deleting the DLL and PDB files in the web service bin and obj files.
Try clicking "View in Browser" in Visual Studio.
If you previously got the source file mismatch error, Visual Studio might have added the filename to a black list. Check your solution properties. Choose "Common Properties -> Debug Source Files" on the left side of the dialog box. If your web service source files appear in the field "Do not look for these source files", delete them.
Unload the project that has the file that is causing the error.
Reload the project.
Fixed
I just had this issue.
I tried all the above, but only this worked:
delete the .pdb file for the solution.
delete the offending .obj files (for the file being reported out of sync)
build the solution.
This fixed the issue for all builds moving forward for me.
In Visual Studio 2017 deleting the hidden .vs folder in the resolved this issue for me.
This is how I fixed the problem in Visual Studio 2010:
1) Change the 'Solutions Configurations' option from "Debug" to "Release"
2) Start debugging
3) Stop debugging and switch the 'Solutions Configurations' option back to "Debug"
This worked for me. Step 3 is optional - it was working fine when I changed it to "Release" but I wanted to change it back.
My solution:
I had included an existing project from a different solution in a new solution file.
I did not notice that when the existing project was rebuilt, it was putting the final output into the NEW solution's output directory. I had a linker path defined to look into the OLD solution's output directory.
Switching my project to search in the new solution's output directory fixed this issue for me.
I had this problem, and it turns out I was running my console application as a windows application. Switching the output type back to console fixed the issue.
I had the same problem. To fix it I used the "Release Mode" to debug in VS2013. Which is sufficient for me, because I'm working in a node js\c++ addon.
My problem was that I had two projects in my solution. The second one was a test project used to call the first one. I had picked the path to the references from the bin folder's release folder.
So whenever I made a change to the first project's code and rebuilt it, it would update the dlls in the debug folder but the calling project was pointing to the release folder, giving me the error, "the source file is different from when the module was built."
Once I deleted the reference to the main project's dll in the release folder and set it to the dll in the debug folder, the issue went away.
In my case, the #Eliott's answer doesn't work.
To solve this problem I had Exclude/Include From Project my deficient file, andalso Clean and Rebuild the solution.
After these actions, my file with my last modifications and the debugger are restored.
I hope this help.
solution:-
the problem is:-
if your some projects in a solution , refer to some other projects,
then sometimes the dll of some projects, will not update automatically, whenever you build the solution,
some projects will have previous build dlls, not latest dlls
you have to go manually and copy the dll of latest build project into referenced project
I was using Visual Studio 2013 and I had an existing project under source control.
I had downloaded a fresh copy from source control to a new directory.
After making changes to the fresh copy, when building I received the error in question.
My solution:
1) Open Documents\IISExpress\config\applicationhost.config
2) Update virtualDirectory node with directory to the fresh copy and save.
My problem was that I had a webservice in the project and I changed the build path.
Restoring the default build path solved my issue.
I had this same problem and I followed the majority of the guidance in the other answers posted here, nothing seemed to work for me.
I eventually opened IIS and recycled the application pool for my web application. I have IIS version 8.5.9600, I right-clicked my web application, then: Deploy > Recycle > Recycle application pool > OK.
That seems to have fixed it, breakpoints now being hit as expected. I think that doing this along with deleting the bin and obj folders helped my situation.
Good luck!
I know this is an old question but I just had the same problem and wanted to post here in case it helps someone else. I got a new computer and the IT dept merged my old computer with the new one. When I set up TFS, I mapped a different local path than what I was previously using, to an additional internal drive. The old path still existed from the merged data on my hard drive so I could still build and run. My IIS paths were also pointing to the old directory. Once I updated IIS to the correct path, I was able to debug just fine. I also deleted the old directory for good measure.
I also experienced that. I just open the obj folder on the project and then open the debug folder delete the .pdb file and that's all.
This error also happens if you try to make changes to a source file that is not part of the project.
I was debugging a method from a .dll of another one of my projects, where Visual Studio had quite helpfully loaded the source because the .dll had been built on the same machine and it knew the path to the source. Obviously, changing such a file isn't going to do anything unless you rebuild the referenced project.
Delete all breakpoints.
Rebuild.
Done
At Visual Studio 2015, using C++, what fixed for me the the source file is different from when the module was built problem was
restart Visual Studio.
Check if the location you pointed to using mex() in Matlab is correct (contains lib and obj files which are modified to the last date you compiled the library in Visual studio).
If this is not the case:
Make sure you are compiling Visual studio in a mode that saves .lib files :
properties -> Config properties -> General -> Config type -> static library
properties -> Config properties -> General -> Target extension=.lib (instead of exe)
Make sure the output and intermediate directories match the Matlab directory in
properties -> Config properties -> General -> Output directory
properties -> Config properties -> General -> Intermediate directory
I get this issue when debugging sometimes w/ Visual Studio but when the application is served by IIS. (we have to develop in this form for some complicated reasons that have to do with how the original developer setup this project.)
When I change the file and rebuild, that fixes it a lot of the time. I know that sounds silly, but I was just trying to debug some code to see why it's doing something weird when I haven't changed it in a while, and I tried a dozen things from this page, but it was fixed just by changing the file..
In my case, the problem was that the debugger exe path was pointing to a net5.0 bin folder. I am using net6.0, so I should've updated the exe path back when I updated the target framework. Works fine now.
Debug-> start without debugging.
This option worked for me. Hope this helps!