error: Unable to find vcvarsall.bat

Question

I tried to install the Python package dulwich:

pip install dulwich 

But I get a cryptic error message:

error: Unable to find vcvarsall.bat 

The same happens if I try installing the package manually:

> python setup.py install running build_ext building 'dulwich._objects' extension error: Unable to find vcvarsall.bat 

Answer 1

Update: Comments point out that the instructions here may be dangerous. Consider using the Visual C++ 2008 Express edition or the purpose-built Microsoft Visual C++ Compiler for Python (details) and NOT using the original answer below. Original error message means the required version of Visual C++ is not installed.

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For Windows installations:

While running setup.py for package installations, Python 2.7 searches for an installed Visual Studio 2008. You can trick Python to use a newer Visual Studio by setting the correct path in VS90COMNTOOLS environment variable before calling setup.py.

Execute the following command based on the version of Visual Studio installed:

• Visual Studio 2010 (VS10): SET VS90COMNTOOLS=%VS100COMNTOOLS%
• Visual Studio 2012 (VS11): SET VS90COMNTOOLS=%VS110COMNTOOLS%
• Visual Studio 2013 (VS12): SET VS90COMNTOOLS=%VS120COMNTOOLS%
• Visual Studio 2015 (VS14): SET VS90COMNTOOLS=%VS140COMNTOOLS%

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WARNING: As noted below, this answer is unlikely to work if you are trying to compile python modules.

See Building lxml for Python 2.7 on Windows for details.

Answer 2

I found the solution. I had the exact same problem, and error, installing 'amara'. I had mingw32 installed, but distutils needed to be configured.

1. I have Python 2.6 that was already installed.
2. I installed mingw32 to C:\programs\mingw\
3. Add mingw32's bin directory to your environment variable: append c:\programs\MinGW\bin; to the PATH

4. Edit (create if not existing) distutils.cfg file located at C:\Python26\Lib\distutils\distutils.cfg to be:

   [build] compiler=mingw32 

5. Now run easy_install.exe amara.

Make sure environment is set by opening a new cmd.exe.