Trying to launch ZDL on a modern Windows system will sometimes result in a very unhelpful error box pop-up that simply reads, MSVCR100.dll is missing. This is not referring to just the DLL but it’s what first causes an issue so that’s what the error returns. So how do you fix this?

This is because the system is missing the Microsoft Visual C++ 2010 Service Pack 1. To fix, go to the Microsoft Download Center, search for this redistributable, and download both the x86 and x64 versions. Install these, and then try to launch ZDL. It may take a minute, but should work just fine.