Hi, since I needed to build latest ECL for current Windows 10 (free! did you know? I didn't!) with the command line tools included in (free as in "register first") Visual Studio Express 2015, I encountered an annoyance while building the garbage collector library: The build in 'ecl/msvc' (using nmake.exe) failed early complaining about not being able to find both 'libcmt.lib' and 'libvcruntime.lib'. Since I struggled a while before finding the (simple) solution, I wanted to put it here, just for reference. The following fixed it for me: Copy both files (see above) from / to: C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\lib\onecore\amd64\ C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\lib\amd64\ Paul P.S. about Windows 10 being "free": search the web for yourself, but it's true: you can download an official ISO image of Windows 10 form the MS website, and you're not required to purchase a license, if you agree to not being able to customize its look and feel...; so, you basically get both their OS and compiler suite for nothing more than the patience of downloading some GB, and providing 'some' email address for registering an account...