Python PIP Error: Unable to find vcvarsall.bat
Error: Unable to find vcvarsall.bat
Although I had Visual Studio 2010 installed, and made sure the batch file exists and the batch file creates the compilation environment correctly, I still got this error.
The short answer (credits to fmuecke) is to point the environment variable VS90COMNTOOLS to the value of VS100COMNTOOLS.
This solved the issue.