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

What's going on? Python modules can be part written in C or C++ (typically for speed). If you try to install such a package with Pip (or setup.py), it has to compile that C/C++ from source. Out the box, Pip will brazenly assume you the compiler Microsoft Visual C++ installed. If you don't have it, you'll see this cryptic error message "Error: Unable to find vcvarsall.bat".

The prescribed solution is to install a C/C++ compiler, either Microsoft Visual C++, or MinGW (an open-source project). However, installing and configuring either is prohibitively difficult. (Edit 2014: Microsoft have published a special C++ compiler for Python 2.7)

The easiest solution is to use Christoph Gohlke's Windows installers (.msi) for popular Python packages. He builds installers for Python 2.x and 3.x, 32 bit and 64 bit. You can download them from http://www.lfd.uci.edu/~gohlke/pythonlibs/

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If you too think "Error: Unable to find vcvarsall.bat" is a ludicrously cryptic and unhelpful message, then please comment on the bug at http://bugs.python.org/issue2943 to replace it with a more helpful and user-friendly message.

For comparison, Ruby ships with a package manager Gem and offers a quasi-official C/C++ compiler, DevKit. If you try to install a package without it, you see this helpful friendly useful message:

Please update your PATH to include build tools or download the DevKit from http://rubyinstaller.org/downloads and follow the instructions at http://github.com/oneclick/rubyinstaller/wiki/Development-Kit

You can read a longer rant about Python packaging at https://stackoverflow.com/a/13445719/284795

Answer 2

You can install compiled version from http://www.lfd.uci.edu/~gohlke/pythonlibs/

Answer 3

I spent almost 2 days figuring out how to fix this problem in my python 3.4 64 bit version: Python 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:44:40) [MSC v.1600 64 bit (AMD64)] on win32

Solution 1, hard: (before reading this, read first Solution 2 below) Finally, this is what helped me:

1. install Visual C++ 2010 Express
2. install Microsoft Windows SDK v7.1 for Windows 7
3. create manually file vcvars64.bat in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\amd64 which contains CALL "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x64 or other path depending on where you have yours installed
4. (this seems to be optional) install Microsoft Visual Studio 2010 Service Pack 1 together with Microsoft Visual C++ 2010 Service Pack 1 Compiler Update for the Windows SDK 7.1

5. after that I tried to pip install numpy but received the following error:

   File "numpy\core\setup.py", line 686, in get_mathlib_info
   raise RuntimeError("Broken toolchain: cannot link a simple C program")
   RuntimeError: Broken toolchain: cannot link a simple C program
   

   I changed mfinfo to None in C:\Python34\Lib\distutils\msvc9compiler.py per this https://stackoverflow.com/a/23099820/4383472

6. finally after pip install numpy command my avast antivirus tried to interfere into the installation process, but i quickly disabled it

It took very long - several minutes for numpy to compile, I even thought that there was an error, but finally everything was ok.

Solution 2, easy: (I know this approach has already been mentioned in a highly voted answer, but let me repeat since it really is easier) After going through all of this work I understood that the best way for me is just to use already precompiled binaries from http://www.lfd.uci.edu/~gohlke/pythonlibs/ in future. There is very small chance that I will ever need some package (or a version of a package) which this site doesn't contain. The installation process is also much quicker this way. For example, to install numpy:

1. donwload numpy‑1.9.2+mkl‑cp34‑none‑win_amd64.whl (if you have Python 3.4 64-bit) from that site
2. in command prompt or powershell install it with pip pip install numpy‑1.9.2+mkl‑cp34‑none‑win_amd64.whl (or full path to the file depending how command prompt is opened)

Answer 4

I had this problem using Python 3.4.1 on Windows 7 x64, and unfortunately the packages I needed didn't have suitable exe or wheels that I could use. This system requires a few 'workarounds', which are detailed below (and TLDR at bottom).

Using the info in Jaxrtech's answer above, I determined I needed Visual Studio C++ 2010 (sys.version return MSC v.1600), so I installed Visual C++ 2010 Express from the link in his answer, which is http://go.microsoft.com/?linkid=9709949. I installed everything with updates, but as you can read below, this was a mistake. Only the original version of Express should be installed at this time (no updated anything).

vcvarsall.bat was now present, but there was a new error when installing the package, query_vcvarsall raise ValueError(str(list(result.keys())))ValueError: [u'path']. There are other stackoverflow questions with this error, such as Errors while building/installing C module for Python 2.7

I determined from that answer that 2010 Express only installs 32-bit compilers. To get 64-bit (and other) compilers, you need to install Windows 7.1 SDK. See http://msdn.microsoft.com/en-us/windowsserver/bb980924.aspx

This would not install for me though, and the installer returned the error installation failed with return code 5100. I found the solution at the following link: http://support.microsoft.com/kb/2717426. In short, if newer versions of x86 and x64 Microsoft Visual C++ 2010 Redistributable's are installed, they conflict with the ones in SDK installer, and need uninstalling first.

The SDK then installed, but I noticed vcvars64.bat still did not exist in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin, nor its subfolders. vcvarsall.bat runs the vcvars64 batch file, so without it, the python package still wouldn't install (I forgot the error that was shown at this time).

I then found some instructions here: http://www.cryptohaze.com/wiki/index.php/Windows_7_Build_Setup#Download_VS_2010_and_Windows_SDK_7.1 Following the instructions, I had already installed Express and 7.1 SDK, so installed SDK 7.1 SP1, and did the missing header file fix. I then manually created vcvars64.bat with the content CALL setenv /x64. I will paste all those instructions here, so they don't get lost.

Step 1 is to download Visual Studio Express 2010.

http://www.microsoft.com/visualstudio/en-us/products/2010-editions/express is a good place to start. Download the installer, and run it (vc_web.exe). You don't need the SQL 2008 additional download.

You'll also need the Windows SDK (currently 7.1) for the 64-bit compilers - unless you want to do 32-bit only builds, which are not fully supported...

http://www.microsoft.com/en-us/download/details.aspx?id=8279 is a good starting point to download this - you'll want to run winsdk_web.exe when downloaded!

The default install here is just fine.

Finally, download and install the Windows SDK 7.1 SP1 update: http://www.microsoft.com/en-us/download/details.aspx?id=4422

And, to fix missing header file, VS2010 SP1. http://www.microsoft.com/downloads/en/confirmation.aspx?FamilyID=75568aa6-8107-475d-948a-ef22627e57a5

And, bloody hell, fix the missing batch file for VS2010 Express. This is getting downright absurd.

In C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\amd64, create "vcvars64.bat" with the following (you will need to be running as administrator):

CALL setenv /x64

My python package still did not install (can't recall error). I then found some instructions (copied below) to use the special SDK 7.1 Command Prompt, see: https://mail.python.org/pipermail/distutils-sig/2012-February/018300.html

Never mind this question. Somebody here noticed this item on the menu: Start->All Programs->Microsoft Windows SDK v7.1 ->Windows SDK 7.1 Command Prompt

This runs a batch job that appears to set up a working environment for the compiler. From that prompt, you can type "setup.py build" or "setup.py install".

I opened the Windows SDK 7.1 Command Prompt as instructed, and used it to run easy_install on the python package. And at last, success!

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TLDR;

1. Install Visual Studio Express 2010 (preferably without updated redistributables or SQL server).
2. Install Windows 7.1 SDK
3. Instal SDK 7.1 SP1 update, and VS2010 SP1 header file fix (this step may not be required).
4. Manually create C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\amd64\vcvars64.bat with content CALL setenv /x64
5. Start->All Programs->Microsoft Windows SDK v7.1 ->Windows SDK 7.1 Command Prompt to open special x64 command prompt, which can then be used with python/easy_install/pip/etc (including those in virtual_envs).

Answer 5

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 6

I tried many solutions but only one worked for me, the install of Microsoft Visual Studio 2008 Express C++.

I got this issue with a Python 2.7 module written in C (yEnc, which has other issues with MS VS). Note that Python 2.7 is built with MS VS 2008 version, not 2010!

Despite the fact it's free, it is quite hard to find since MS is promoting VS 2010. Still, the MSDN official very direct links are still working: check https://stackoverflow.com/a/15319069/2227298 for download links.