Windows Install

/!\ You probably want the prepackaged Windows version from here.

In this web page firstly you will find a 'standard' procedure to install and config Mercurial from sources under Windows. It should satisfy you generally. If not, you could continue reading for various tips and references provided by various contributors in history. Some of them are valuable although some of them are a bit out of date.

1. Compile and install

When installing Mercurial from source, you have two choices: Compile optimized version with C extensions for increased performance, or use the pure Python method. The latter doesn't require a C compiler to be present on Windows system (which it usually isn't).

You'll need Python and Mercurial source in either case.

1. Download Python binary such as python-2.6.2.msi from Install it to somewhere you can find later - C:\Python26 as default.

2. Download Mercurial source such as mercurial-1.3.tar.gz from Unpack it to C:\Mercurial_src.

Caution: Check to make sure you didn't unpack it to C:\Mercurial_src\mercurial-1.3 or similar.

1.1. "Standard" procedure for building optimized version

Caution: Don't use Active Python in, or you will probably fail to build Mercurial from source.

3. Download the MinGW binary (such as MinGW-5.1.4.exe) from Download it to a writable directory. Install it to C:\MinGW as default, with other default opinions ("Current", and then "min").

4. Add C:\MinGW\bin to PATH env. It should look like

C:\Python26;bla bla bla;C:\MinGW\bin

Caution: The order is important. Keep it or you will probably fail to build.

5. In Windows command prompt, change dir to C:\Mercurial_src. Then run following commands:

python build --force -c mingw32
python install --force --skip-build

1.2. Building pure Python alternative

3. Change dir to C:\Mercurial_src and run following commands:

C:\Python26\python.exe --pure build_py -c -d . build_ext -i build_mo --force
C:\Python26\python.exe --pure install --force

2. Setup environment

6. Download KDiff3 such as KDiff3Setup_0.9.95.exe from Install it into C:\Program Files\KDiff3 as default.

7. Add C:\Program Files\KDiff3 to PATH env.

8. Create Mercurial config file:

notepad "C:\Documents and Settings\[your_name]\Mercurial.ini"


notepad "C:\Users\[your_name]\Mercurial.ini"

Fill in content below into the config file:

editor = Notepad
username = your_name <your_email_address>

kdiff3.args=--L1 base --L2 local --L3 other $base $local $other -o $output

9. (Nice to have) Copy from C:\Python26\Scripts\hg to C:\Python26\ As C:\Python26 is in your PATH env already, you could call to run Mercurial at any location. As you may installed or will install binary Mercurial or TortoiseHG, you could always call to run this script version of Mercurial, or call hg which will lead you to the binary version.

3. Various tips and references

3.1. Overview

To install Mercurial from sources under Windows, you need

If you are using's Python, you will find that the win32 API extensions make a huge performance difference when you use the clone command (but see the caveats below about hardlinks on Windows). If you are using Python 2.4, you will also need mfc71.dll. (These extensions are already shipped as part of ActivePython, but ActivePython is not completely open source software.)

See BuildingWindowsInstaller for instructions to build a Mercurial installer. BuildingOnWindows has some hints about how to build Mercurial on Windows.

This pages describes some issues you may meet when trying to install Mercurial, and how to solve them.

Ideally, you would only need to run

python install --force`

in the directory where you unpacked the sources, and everything would "just work". The use of -f/--force switch makes sure that any old installation is overwritten.

3.2. Build tips

3.2.1. MingW32 Using MingW32

By default, Python and ActivePython will look for Microsoft Visual C to compile the extensions, so you have to tell to use the MingW32 compiler instead. You can do this by running:

python build --force -c mingw32 python install --force --skip-build

or more briefly:

python build -f -c mingw32 install -f`

If you are not familiar with mingw32, you will first need to download and install the following packages, in the order given:


Afterwards, download and install the following package, installing it in the directory where you installed the msys package (i.e. c:\msys\1.0\)


You can find them at

Then add the Python and mingw directories to your PATH, and run your build from the command prompt:

set PATH=%PATH%;c:\python24;c:\msys\1.0\mingw\bin`

If you encounter a compiler error in Mercurial versions 0.9.2 and up, you may need libpython24.a in PYTHONPATH\libs. If that's the case, run this command:

pexports C:\WINDOWS\system32\python24.dll > python24.def
dlltool --dllname C:\WINDOWS\system32\python24.dll --def python24.def --output-lib C:\Python24\libs\libpython24.a

The above script should then run properly. Easier MingW32 based build via Cygwin

It is easier to install MinGW32 via Cygwin as it has a single graphical installer. After installing, mingw32 via Cygwin installer (setup.exe), add cygwin bin directory to the path and follow the mingw32 build instructions. e.g.

set PATH=%PATH%;c:\python24;c:\cygwin\bin
python build --force -c mingw32
python install --force --skip-build

3.2.2. MS Visual Studio

If you are going to use MS Visual C++, you need to use the same version of the compiler as the one which was used to build the Python interpreter. For example:

It is possible to force Python to use the compiler that you currently have, even if it's not strictly matching, but since Mercurial 1.3 (more precisely since 7de68012f86e and the introduction of posixfile in the osutil.c extension), the resulting Mercurial installation will crash, probably due to mismatches in the runtime.

(Note: If you take care of backing out 7de68012f86e and related changes (b6d0fa8c7685 and 835a51e63c5b), then building Mercurial with a different compiler would still work using the DISTUTILS_USE_SDK=1 trick. Refer to a previous version of this wiki page if you really need to build Mercurial this way.)

3.3. Install tips

3.3.1. Where is my Mercurial?

By default, Mercurial (the executable) gets installed in a Scripts folder under your Python installation folder.

You can create a small batch file in a folder which is present in your path (e.g. your Windows installation folder) to help you launch Mercurial.

If you are running a Windows version of the 9x series (Windows 95, 98, or ME), create a file called hg.bat with the following content:

@echo off
shift python<path-to-Scripts-folder>\hg %0 %1 %2 %3 %4 %5 %6 %7 %8 %9

For example, if you installed Python in c:\Python, the content of the file would be

@echo off
shift python c:\python\hg %0 %1 %2 %3 %4 %5 %6 %7 %8 %9

Under Windows NT, create a file called hg.cmd with the following content:

@python <path-to-Scripts-folder>\hg %*

For example, if you installed Python in c:\python, the content of the file would be

@python c:\python\Scripts\hg %*

An alternative scheme that works better for some is to search for hg on the PATH. If you are using hg.exe it should work fine. For the Python version of hg you should be able to simply rename 'hg' to '' and assuming you have the .py extension configured it will be invoked. It is invoked, but there is a long standing redirection bug in Windows, and on XP there are sometimes problems with exit statuses being lost with this form of execution. So the following batch file is a solution -- place it in your PATH and it will find 'hg' without a .py extension in you PATH and invoke it properly: (name the file hg.cmd)

@echo off
for /f %%i in ("hg") DO set HGSCRIPT="%%~$PATH:i"
if %HGSCRIPT% == "" (
    echo Cannot find hg on PATH
    exit /b 1
python %HGSCRIPT% %*

An alternative is to add .py to the PATHEXT environment variable. Provided you have .py files set-up to run automatically when invoked, this allows you to run Python scripts from the command line without the ending .py. This option also works if you are using UTF-8 in the Windows console (i.e code page 65001) which causes BAT and CMD files to stop working.

3.3.2. Where should I put my initialization/configuration files?

Refer to this manual page for an overview.

Note: For installations of 32-bit Python on 64-bit Windows, the HKLM key should actually be under HKLM/SOFTWARE/Wow6432Node/Mercurial. Put the path to your INI file in the (Default) value that is created when you create the Mercurial key.

3.3.3. Other miscellaneous issues

WinZip7 does not seem to create empty files when extracting from .tar files. But WinZip9 is fine.

Earlier versions of mercurial had trouble handling tildes in glob patterns on windows. Upgrade if you encounter this problem.

3.3.4. Using the SSH protocol

Three solutions:

  1. Install PuTTY and follow the instructions here: Accessing SSH Repositories From Windows

  2. Install cygwin and OpenSSH, then use the cygwin shell where ssh will be automatically in the PATH.
  3. Install cygwin and OpenSSH, and modify Mercurial.ini to call the cygwin-installed ssh executable.
  4. Install git, which has has ssh binaries, or download and unzip this file someplace in your PATH.

Edit the Mercurial.ini file to have the following entry:

[ui] ssh = C:\cygwin\bin\ssh.exe

3.3.5. Fix the PATH problem on Windows

If you try to use hg inside a directory that has a "mercurial" subdirectory (such as when working on the Mercurial sources), Python may not be able to load the binary modules needed by Mercurial, and you may get a stack trace error similar to:

File "C:\projects\hg\mercurial\", line 54, in module
     return object.__getattribute__(self, 'importer').module()
File "C:\projects\hg\mercurial\", line 30, in module
File "C:\projects\hg\mercurial\", line 9, in ?
     import struct, bdiff, util, mpatch
ImportError: No module named bdiff

See the mail list thread "Fix the path problem on Windows..." but essentially Python on Windows ends up with the current directory automatically added to the Python search path before the site libraries. So if you run hg in its own repository Python gets confused, and can't find the extensions needed. There is a candidate patch that removes the current directory, but there is an arguably better workaround from K.Thananchayan. Simply add a registry entry (replacing 2.4 with the version of Python)

HKLM/SOFTWARE/Python/PythonCore/2.4/PythonPath/XXX    (Default) REG_SZ "YYY"

see HardlinkedClones

3.5. Default editor

The default editor for commit messages is vi. The Windows installer creates a ''Mercurial.ini'' file that sets it to notepad. You can set the EDITOR (or HGEDITOR) environment variable to specify your preference, or set it in ''mercurial.ini'':

editor = whatever


WindowsInstall (last edited 2013-07-19 10:57:21 by rcl)