See the new test class in #901 `AccessViolationException` gets thrown in the line `PyImport_ImportModule("platform")` in `Runtime.InitializePlatformData` when a release build is tested using NUnit console runner. `nunit3-console.exe --x86 src\embed_tests\bin\publish\Python.EmbeddingTest.dll` Removal of initialization code makes tests succeed: ```csharp [OneTimeSetUp] public void SetUp() { PythonEngine.Initialize(); } [OneTimeTearDown] public void Dispose() { PythonEngine.Shutdown(); } ``` The initialization code on its own may not be the cause, as there are other classes, that use the same pattern. Must be something in conjunction with the actual tests. Note, that disabling feature implemented by #901 by commenting out code in `TypeManager` does not resolve the problem, e.g. it crashes anyway.