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My VB sports results application, established and developed over many years, now runs in many W10 computers from the UK to Russia to Australia, but completely fails to start with no e.Exception.Message and no e.Exception.StackTrace for two key users in France and Italy, where the Startup form doesn't even show. The project is set to .NET 4.0.0.0
Setting my system to French and Italian fails to provide any clues, for me it always runs fine. Could this be their AV system blocking it? What can I do to trace what is causing this issue?
Most AV(s) I would say all of them will show a popup message that it was blocking a program from executing.
I would say to put logging code in the program and log where the program execution is at when it fails.
In case of Forms application, did you try to handle ThreadException and UnhandledException events (https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.application.threadexception?view=netframework-4.8)?
See Application page of VB project properties - Visual Studio. Do you have a handler for the UnhandledException event?
Yes - ApplicationEvents is the only thing that runs, at which time both e.Exception.Message and e.Exception.StackTrace are blank so whatever is causing this happens before any Startup form code runs. It's as though it is triggered by a declaration in the Friend / Private region, but why then should it fail for only a couple of users and work for everyone else?
I do not know if anything would be in the system events but have they looked there?
Usually when an application fails like this it's from a catastrophic runtime exception which can be duplicate via Environment.FailFast does. Assume something is missing or corruption with a DLL. Usually if an anti-virus program is the culprit there may or may not be a history log to track down.
Finally, ask the user to look at the system logs to see if there was a report pointing to your application failing to run. This can be difficult if the user is not familiar with accessing the event logs.
Hi there, the prime user who had this issue has now rebuilt their pc and the issue has disappeared, so either it was their AV (unlikely I think) or their .NET 4.7 library was not up-to-date or maybe corrupted. Clearly the app runs in a clean environment, so I think this is effectively the end of this issue. Thanks to all for suggestions.
Final final comment - just discovered that the user still having this issue is running VMWare Workstation 15. This is apparently allowing my code to run to the point where a data file is read, then it crashes with the e.Exception.Message blanked. His setup won't run my subsequent .NET email reporting system either, it's a total washout. I don't know whether VMWare should avoid this, but I'm sure this is the culprit.