LoadLibraryExW() fails, last error is ERROR_MOD_NOT_FOUND, but no missing dependencies?

Question

A customer is using our dll which is creating a child process which uses an open source library, which ultimately fails because of a call to LoadLibraryExW(), the last error

Answer 1

The best way is to use loader snaps. Basically you use gflags.exe (which is included with windbg) to enable loader snaps; then, run the process with the debugger attached. Loader snaps will enable the loader to print out dbg messages of the process and it will print the failures.

gflags.exe -i yourcode.exe +sls
windbg yourcode.exe

Answer 2

Your dependencies might be present on the system but they could be in a folder that is not part of the search order during LoadLibraryExW(). A SetDllDirectory() or AddDllDirectory() call would ensure that the folder containing the dependencies is searched during the LoadLibraryExW() call

Answer 3

Use the Profiling option of the Dependency Walker on your application. Possibly the library is trying to resolve some APIs dynamically (using LoadLibrary/GetProcAddress) and this won't show up in the static dependencies.