How do I fix a .NET windows application crashing at startup with Exception code: 0xE0434352?

If you are getting that error from Event Viewer, you should see another error event (at least one) from the Source ".NET Runtime". Look at that error message as it will contain the Exception info.

0xE0434352 is the exception code for all .NET exceptions so that won't tell you much. How did you got this exception code? The event log?

Your best bet is to use a debugger to get more information. If the Visual Studio debugger won't help you, then you might need to check out WinDbg with SOS. See here and here for an introduction. Let it break on the exception, and see if you can get more information on the why.

If you suspect it is an issue when loading assemblies you might want to check out the Fusion Log.

I'm not sure if this will help anyone or not, but since it was my problem, I figure it's worth mentioning:

I was getting this error, and it turned out to be a problem with the platform for which the EXE was built. We had it building for x86, and it needed to be x64, because of an Oracle reference in the project. When we made that change, the problem went away. So, see if you have any similar conflicts.