C++/CLI Missing MSVCR90.DLL

Question

I have a c++/cli dll that I load at runtime and which works great in debug mode. If I try and load the dll in release mode it fails to load stating that one or more dependencies

Answer 1

MSVCR90 is the runtime for Visual Studio 2008. If you are running your application on your development PC, then you should have the debug and release runtimes installed (as part of Visual Studio) but it is possible something has gone awry with your install, or that VS2010 doesn't actually include the older runtimes. If you're trying to run the Release on a different PC, then it just needs the runtime installed.

Either way, you may be able to fix it by installing the Visual Studio 2008 redistributable - but make sure you get the right download for your PC (x86 or x64).

In previous versions of VS, you needed the runtime for the version you were compiling with, so if VS2010 follows this precedent you'd need MSVCR100, not MSVCR90 - which suggests that you may not have recompiled the dll with VS2010 - doing so may be another approach to get it running on your PC (using the redist that is in your VS2010 install) but beware that you will still need other users to install the appropriate (VS2010) redistributable on their PC.

As for "Any CPU" versus "x86", this is a problem only on a 64-bit computer. On those systems a 64-bit application can't link dynamically to 32-bit dlls. If you compile your application as "Any CPU" it will be JIT compiled to be 64-bit on an 64-bit OS, so will crash if it tries to call any 32-bit dlls directly. THe solution is to build the application targeting "x86" as that forces the JIT compiler to generate 32-bit code (even on a 64-bit machine) and thus ensures compatibility with the dll you wish to call. If the DLL is a managed assembly, then you can use Any CPU on both the app an dll as they will both be JITted to the same format.