System.IO.IOException: The process cannot access the file 'C:\Users\patsupport\AppData\Local\SquirrelTemp\tempa\lib\net45\VirtualBlackBoard_ExecutionStub_ExecutionStub_ExecutionStub_ExecutionStub_ExecutionStub.exe'

[StephanieLayton]

We've recently switched deploying one of our desktop apps from ClickOnce to Squirrel.Windows. The good news is that it is working successfully on most of the client servers. The not-so-good-news is that a few client servers are not happy and we are getting the following error.

System.IO.IOException: The process cannot access the file 'C:\Users\support\AppData\Local\SquirrelTemp\tempa\lib\net45\VirtualBlackBoard_ExecutionStub.exe' because it is being used by another process.

Having searched, I haven't seen anything that matches this error with the ..ExecutionStub.exe, but similar issues mention a possible anti-virus software being a problem Is this b/c of Anti-virus software?

Currently working in tandem to have customers turn off to experiment but we haven't had a customer response yet to do so. And if it is, is there a work around. And if it is something else, anyone provide a fix for this issue.

Hopefully this is enough info to get started on a discussion and any insight and help on getting this resolved is appreciated.

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2020-03-05 10:19:57> Program: Starting Squirrel Updater: --releasify E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\VirtualBlackBoard.19.4.0.nupkg --releaseDir E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\SquirrelPackaging --no-msi --no-delta
2020-03-05 10:19:57> Program: Bootstrapper EXE found at:E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\squirrel.windows.1.9.1\tools\Setup.exe
2020-03-05 10:19:57> Program: Creating release package: E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\SquirrelPackaging\VirtualBlackBoard.19.4.0.nupkg
2020-03-05 10:19:57> ReleasePackage: Creating release package: E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\SquirrelPackaging\VirtualBlackBoard.19.4.0.nupkg => E:\Program Files (x86)\Generic Ed Company\genericEdApp 4.1\cabs\VirtualBlackBoard\SquirrelPackaging\VirtualBlackBoard-19.4.0-full.nupkg
2020-03-05 10:20:00> ReleasePackage: Extracting dependent packages: []
2020-03-05 10:20:00> ReleasePackage: Removing unnecessary data
2020-03-05 10:20:00> ReleasePackage: No release notes found in C:\Users\patsupport\AppData\Local\SquirrelTemp\tempa\VirtualBlackBoard.nuspec
2020-03-05 10:20:01> Unhandled exception: System.AggregateException: One or more errors occurred. ---> System.IO.IOException: The process cannot access the file 'C:\Users\patsupport\AppData\Local\SquirrelTemp\tempa\lib\net45\VirtualBlackBoard_ExecutionStub_ExecutionStub_ExecutionStub_ExecutionStub_ExecutionStub.exe' because it is being used by another process.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access)

[anaisbetts]

Yes, this error is typically caused by third-party antivirus blocking the installer from writing files. Are you signing your installer and executables? This typically dramatically reduces the amount of AV-related nonsense. Make sure that you're using the signing facility built into Squirrel, because it ensures that every file gets signed, including the execution stubs

[StephanieLayton]

Ok. Thank you for the confirmation.

The AV software is told to skip a certain directory and we'd like the processing to happen there. Is there a way to tell Squirrel.Windows to do this processing in a specific/custom location?

[Alonzzzo2]

I'm getting the same error occasionally when releasifying and it's a big issue...
signing the files won't help (haven't tried) simply cause at the Releasify method, the signing occurs AFTER the releasify process failes.
It failed on:
rp.CreateReleasePackage(Path.Combine(di.FullName, rp.SuggestedReleaseFileName), packagesDir, contentsPostProcessHook: pkgPath => { new DirectoryInfo(pkgPath).GetAllFilesRecursively() .Where(x => x.Name.ToLowerInvariant().EndsWith(".exe")) .Where(x => !x.Name.ToLowerInvariant().Contains("squirrel.exe")) .Where(x => Utility.IsFileTopLevelInPackage(x.FullName, pkgPath)) .Where(x => Utility.ExecutableUsesWin32Subsystem(x.FullName)) .ForEachAsync(x => createExecutableStubForExe(x.FullName)) .Wait();

and more specifically at:
Utility.ExecutableUsesWin32Subsystem

Where it tries to open a stream of file but can't cause it's already in use (which I fail to understand how it happens only sometimes...)

Any suggestions?
OP, did you ever solve this issue?