Dll - A Fatal Error Has Occurred Loading The Metadata For Mscorlib

When Mono’s mono_image_open_from_data_with_name() function tries to read the PE/COFF structure of mscorlib.dll :

Few error messages induce panic in a developer or system administrator quite like the phrase "Fatal Error." When that error references mscorlib.dll , the panic is often justified. This specific error— "A fatal error has occurred loading the metadata for mscorlib.dll" —is a show-stopper. It prevents applications from launching, crashes services, and can even prevent development environments like Visual Studio from starting.

Here are the steps to resolve the issue, ordered from easiest to most advanced.

A fatal error has occurred while loading the metadata for mscorlib.dll