Exception: 0xC000041D (An unhandled exception was encountered during a user callback) happens when compiling in .NET 4.5 but not on .NET 4.0

I have a C# app that uses native DLLs through LoadLibrary. The app runs perfectly under .NET 4.0.

When I try to compile that same app targeting .NET Framework 4.5, the application keeps crashing in scenarios where it works on .NET 4.0.

I tried everything to my knowledge, including:

• setting ThrowUnobservedTaskExceptions
• setting legacyCorruptedStateExceptionsPolicy
• setting legacyUnhandledExceptionPolicy

They all didn't work.

Thoughts?