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Xamarin.Mac application hang when interacting with filesystem for end-users

I'm working on an internal company desktop app that gets distributed via an internal intranet site. The app is written in C# using Xamarin.Mac and Visual Studio for Mac and works fine locally until I compress the *.app file and upload it to the intranet site to be downloaded by end users.
When a user (including myself), downloads and launches the application it completely locks up trying to perform any actions where it interacts with the users local filesystem (No errors or warnings are displayed/no crashes are seen, it just stops executing any more code. The UI continues to update but nothing else happens).
The weird part is that if you right-click the '*.app' file, select "Show Package Contents" then browse into 'Content' > 'MacOS' and double-click the copy of app contained in there, everything works fine and without any problems.
I'm not an expert on OSX so I'm really struggling to understand what could be causing this behaviour and also what the difference is between launching a Xamarin.Forms app via the '*.app' file and the executable located inside this at 'ProgramName.app/Content/MacOS/ProgramName'.
I've checked/confirmed the app isn't being sandboxed and it's being signed/notarized using the correct distribution certificates/provisioning profiles as far as I can tell, so as far as I'm aware there shouldn't be any security restrictions preventing the required filesystem access. Unless there's something I'm missing.
Is there any way I can get more insight into what is causing this behaviour, such as any debugging tools I can use to understand/view any potential problems with the app itself/the way it's being built?
Thanks!

Managed to finally get to the bottom of this one: The issue was because of a security system Apple have in-place known as 'App Translocation'.
There's a description of this here for anyone who isn't familiar: https://lapcatsoftware.com/articles/app-translocation.html - The tl;dr is that downloaded applications are marked as 'Quarantined' and when ran they're copied to a virtual read-only file system and executed from there. This prevents the application from having any access to the local filesystem (Regardless of if the application is signed/notarized or downloaded from a 'trusted' source etc).
There are two ways to 'unquarantine' an application:
Manually move the application to a different location via Finder (e.g. Drag/drop it into '/Applications' or '~/Documents' (Note: Moving the folder the app is located in/was extracted too isn't enough - You have to physically move the *.app file itself). Apple treats this action as the user considering the application as safe and removes the quarantine flag during the move operation (This has to be done via Finder, it cannot be done via command line operations such as mv).
Run the following command from Terminal to remove the quarantine flag:
xattr -dr com.apple.quarantine '/path/to/downloaded/program.app'
You can detect if you're application is being affected by App Translocation in a number of ways, for instance:
Using 'Console' you can see the path of your executable is something like '/private/var/.../AppTranslocation/....' (This is something I spotted in the Console when previously debugging, but I didn't know enough about OSX to understand exactly what I was seeing and initial attempts to understand this didn't yield any useful information at first)
Run the command xattr /path/to/downloaded/program.app. If the following is seen in then output:
com.apple.quarantine
Then it means the application will be affected by App Translocation.

Getting error "Cannot create Active X component" from Windows service but not console Application

I have a Windows service written in c# which keeps listening to one Event Hub in Azure. As soon as a message is received, the service processes the message and does some execution and calculation.
As part of the execution, it launches a application called AutoCal (company's own window's application), which is COM component similar to that of Excel.
Earlier I had a web api which does the same calculation/execution. Upon every request it opens AutoCal and does some processing. I have added the AutoCal DLL as reference in the project.
The code to open AutoCal is something similar:
(AutoCal.Application)Interaction.CreateObject("AutoCal.Application.NewInstance").
When I tested this locally, it has perfectly as expected. But once I hosted this on the server, it has thrown an error saying "Cannot create ActiveX component". To rectify this, I have given permission to open COM components to Application Pool of IIS. This has resolved my issue.
Now that I have a windows service which also open the AutoCal, from where do I give CO component permissions. I have searched for it, but everywhere the solution is for ASP.net only.
How can I rectify this issue for Windows service?
PS: When I have written same code in console application, it is working fine.

Without having exact error logs (can you try looking for related errors in the EventViewer?) it's hard to tell what the problem is.
But I would try the following:
In the start menu type Component services and open it (right click - as admin!)
Go to Component services -> My Computer -> DCOM Config folder
You'll see something like this
Find your COM Application in the tree.
Right click it, open properties, go to Security Tab
It will look like this (never mind the title of the tab in the picture, in your case it should be something like AutoCal):
If it's grayed out, like in my case, you can use the following procedure to change the settings on your system, and make this tab configurable:
Go to Start > Run. Enter regedit
Go to the key that is associated with the DCOM component you want to manage: HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AppID\{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}
Right click on it. Select Permissions
Click Advanced
Change the owner to Administrator or your user account
Click OK
Select Full Control for the Administrators group and owner you selected
Go to Start > Run. Search for services.
Find COM+ System Application. Right click on the service, then click Restart
Once you have the Security tab enabled, you can change the permissions for your COM object. For example - you can allow the user, under which your service runs, to access or activate this COM object.
I hope this helps you, but again, without any additional error info - it's a long shot.

You will want to run it under NETWORK SERVICE, but that's not the problem.
What you're experiencing is all summarised under KB257757.
Considerations for server-side Automation of Office
Your best bet is rewrite it in .Net. If its basic and you're NOT using XML, it might be worth giving that format a go. Back in the day we had to make sure everyone (all our customers) were on MS Office 2003 (turned out IBM were the only ones on 2002 and there's a plugin for 2002 to read 2003).
I know this is not good and I'm sorry to be the bearer of bad news.
Microsoft's stance:
Most server-side Automation tasks involve document creation or editing. Office 2007 supports new Open XML file formats that let developers create, edit, read, and transform file content on the server side. These file formats use the System.IO.Package.IO namespace in the Microsoft .NET 3.x Framework to edit Office files without using the Office client applications themselves. This is the recommended and supported method for handling changes to Office files from a service.

How can I open a file on the user's machine from the backend in C#.Net WebPages?

In my web-app (WebPages, C#.NET) I have a drag and drop file box where user's can drag files from windows explorer and, once dropped, it will save in a given location on a shared drive. This part is working fine. The box looks something like this:
The problem is, that it also reads files from the same directory and my user's would like to be able to open the files from this interface on dblclick. I have written an ajax request with jquery (the ajax, too, is working fine), but I can't seem to get the files to open on the user's machine no matter what I try.
Most references I try and look up point me towards System.Diagnostics.Process.Start(#"<directory goes here>") but this doesn't really do anything. It will open some process on the server side, but nothing opens, either on the server or on the user's machine.
What they'd like to do, for instance, is double click 'Hazcom.xls' and it would use the default associated application to open the file. In this case, of course, Microsoft Excel.
Is this even possible or am I chasing a wild goose here?
Sources I've Tried:
Open file with associated application
http://www.csharp-examples.net/open-file-with-default-application/
How can I open Windows Explorer to a certain directory from within a WPF app?
c# open file with default application and parameters
There have been a few more sources I've tried, as well, but they're all pretty much in the same vein as these.
Additional Info:
The internal Intranet application runs on a server using IIS 8
The solution is desired to be opened on the user's machine and not, say, the server itself.
The path to the files is dynamically changing depending on what they have loaded into the interface.
Though, I'm not expecting this to be a solution viable for client side (jquery) I'd be happy to look into that if that's the only solution available.
I'd also settle for simply opening the file location, instead of the actual file itself, but I've had no luck with this either, for what looks like the same reasons as the original problem.

False positive detection of c# .net program by anti-virus as trojan

I have developed a windows service using C#.Net which collects data and send to my server using custom APIs on a regular interval basis with the client user's permission.
It was working fine until the user installed the anti-virus software (Kaspersky). It, false positively, detected my .exes as PDM:trojan.win32.generic, thrown away into quarantine and removed its service because I am doing web requests using HTTPWebRequest and HTTPWebResponse to push and pull data.
As for temporary, I have white listed .exes and program directory under exclusions rules in anti-virus software program settings and installed service once again. As so it is working fine for now.
But as for final solution, I want to know can we fix this within program itself (programmatically). So that any anti-virus software do not detect it as trojan or any other kind of virus as soon as my program and its service get installed.
Edit - 8th, June 2015
Earlier forgotten to mention that within service .exe it downloads its own latest .exe file to update itself. I wonder if this process is making it to appear as a Trojan.

You can apply to have your program added to the Kasperky whitelist. You may also want to apply for the Kaspersky Lab Trusted Logo.
Other anti virus solutions offer similar whitelist programs, Symantec for example.
Going through these whitelists -IMHO- is the proper way here. If your users place their trust in those solutions your making an effort to be whitelisted i.e. labeled as trustworthy by these solutions should go a long way with your user base.

C# - Fastest way to copy image files in lan computer

I request to read my problem till end. Someone might find it duplicate.
I have a windows application (Client App) a machine & Web Application (Server App) on another machine in same Network.
Client app is capturing screen 5fps and keeping in a local folder which is shared. I have a Windows service which runs on server machine. It moves client images to server directory from client shared folder. I am using File.Move to move the files along with FastDirectoryEnumerator class. These moved files are used to create videos later and also used to show live streaming.
Questions:
Is there any other (Best/Fastest) option to move these files in real time (transfer as soon as it is created at client side)?
I am also interested in file transfer in real time without shared folder.
Update:
My major concerns.
File Transfer should be faster to allow live streaming through my server app (ASP.Net)
Client should retain it if server/connection is not available & transfer as soon as it comes online.

I do not know why you have the server monitoring the client's share, surely this monitoring or as you say, DirectoryEnumerator procedure takes time.
Since the client knows when the image has been captured why don't you send this information to the server immediately from the client? In this way you do not need to monitor clients from server, you do not need to find / enumerate folders, you simply transfer data from client to server as soon as it is available with a specific WCF / Web Service call which takes a stream of bytes as input.

If you have no control over the client app creating the image files you could have a FileSystemWatcher running on the client machine. Add an event handler which will be called whenever the Created event is raised due to a file being created on the file system.
See https://stackoverflow.com/a/15018082/1730317

Things to consider in gaining the best performance out of this type of activity.
For "Real Time" notifications you may want to look at the FileSystemWatcher class. See the documentation for a complete example. Word of warning on this though, when the Operating system is busy it will drop some of these events and you will not be informed of the new file. It's a good idea to program a sweep up loop make doubly sure you have all the files, I have been caught out with this in the past.
You may want to check your hardware configuration, like network latency between the pc and server, and also the disk speeds at both the PC and Server. A low spec SSD is likely to have a big performance benefit in these kinds of operations over spinning disks.