The Basics

64-bit Windows

You will need to be running a 64-bit version of Windows in order to build Thunderbird. To check this in Windows 10, open the start menu and click on the gear icon on the left-hand side of the menu. This will open up the "settings" window. Click on the "System" option and then scroll down to "About". Click on the "About" option and on the new screen next to "System Type" you should see: "64-bit operating system"

Visual Studio

In order to get the necessary libraries in order to build Thunderbird, you will need to install Visual Studio - an IDE from Microsoft. Download the free community edition here.

During installation make sure the following workloads are checked:

• "Desktop development with C++"

• "Game development with C++"

MAPI Headers

Messaging Application Programming Interface (MAPI) is an API for Microsoft Windows which allows programs to become email-aware and the libraries that enable this are required to build Thunderbird on Windows.

Copy 17 of the 18 header files to a Windows SDK include directory so that the build process will find the files, that is C:\Program Files (x86)\Windows Kits\10\Include\10.0.nnnnn.0\shared, where nnnnn is the highest number present on the system. Note that the downloaded Outlook 2010 MAPI Header Files contain 18 fies, of which only 17 are needed. Do not copy MAPI.h, it is already in C:\Program Files (x86)\Windows Kits\10\Include\10.0.17134.0\um\MAPI.h.

As of April 2019, 10.0.17134.0 is needed to compile Thunderbird. Assuming standard installation locations, copy these 17 files to C:\Program Files (x86)\Windows Kits\10\Include\10.0.17134.0\shared.

18/10/2010  16:11             7,334 MAPIAux.h
02/06/2009  17:02             7,938 MAPICode.h
02/06/2009  17:02            22,960 MAPIDbg.h
02/06/2009  17:02            84,644 MAPIDefS.h
02/06/2009  17:02            27,840 MAPIForm.h
02/06/2009  17:02            11,880 MAPIGuid.h
02/06/2009  17:02             2,648 MAPIHook.h
02/06/2009  17:02             5,359 MAPINls.h
02/06/2009  17:02             2,743 MAPIOID.h
02/06/2009  17:02            32,978 MAPISPI.h
02/06/2009  17:02            54,395 MAPITags.h
02/06/2009  17:02            26,467 MAPIUtil.h
02/06/2009  17:02            97,301 MAPIVal.h
02/06/2009  17:02             9,334 MAPIWin.h
02/06/2009  17:02             1,906 MAPIWz.h
02/06/2009  17:02            18,277 MAPIX.h
02/06/2009  17:02             5,012 MSPST.h

MozillaBuild Package

Finally, download the MozillaBuild Package from Mozilla. Accept the default settings, in particular the default installation directory: c:\mozilla-build\. On some versions of Windows an error dialog will give you the option to ‘reinstall with the correct settings’ - you should agree and proceed.

Getting the Code

Once you have run start-shell.bat, you will need to grab the source code if you haven't already.

Get the latest Mozilla source code from Mozilla's mozilla-central Mercurial code repository, and check it out into a local directory source (or however you want to call it). Then, get the latest Thunderbird source code from Mozilla's comm-central Mercurial code repository. It now needs to be placed inside the Mozilla source code, in a directory named comm/ (this is inverse from Thunderbird 59 and earlier):

hg clone https://hg.mozilla.org/mozilla-central source/
cd source/
hg clone https://hg.mozilla.org/comm-central comm/

Mach Bootstrap

In the source directory run the following command to get additional dependencies needed to install Thunderbird:

./mach bootstrap

You will be presented with the following options:

Please choose the version of Firefox you want to build:
  1. Firefox for Desktop Artifact Mode
  2. Firefox for Desktop
  3. GeckoView/Firefox for Android Artifact Mode
  4. GeckoView/Firefox for Android

Please choose option 2 to proceed with a successful build.

This action will install all the remaining libraries and dependencies necessary to build Thunderbird locally.

Building Thunderbird

Now that you have the prerequisites for Windows, make sure you have the source code via the commands on the Getting Started page:

Then you can follow the instructions on the Building Thunderbird page: