“mscorlib.pdb not loaded” yet the mscorlib.dll is NOT missing

Question

I am running my application in VS2012 and I am getting a runtime error;

When I

Answer 1

Goto Tools, Options, Debugging, Symbols and set a cache location. Then hit load in the above and it will fetch the necesary symbols for you and store them in the cache location you provide.

Microsoft's compiler tools create symbols in separate files with a .pdb extension (program database). This allows them to create detached symbols for release binaries. With a symbol server, your IDE can fetch the symbol file matching the specific version of the DLL during debugging. You can configure this system for your own product binaries as well which can be very useful for post-mortem debugging any crashes on end-user machines.

See Microsoft's documentation for more details about using their public symbols.