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Installing Music21 on Mac

Because Apple changes their system details so much from one version of OS X to another, installing music21 is probably the hardest part of the experience. Once you have that set, the rest should be much less painful. Trust us that it should work.

Just follow the instructions below carefully and you shouldn’t have any problems.

Starting Python and Checking the Version

Python is a simple but powerful programming language that music21 is written in and in which you will write your own programs that use music21.

Mac OS X comes with Python, but if you have an older version of OS X (Leopard or earlier) it might not be a new enough version to run music21. Music21 requires Python 2.6 or 2.7 to run. Python 3 is not yet supported.

To determine the Python version you have installed, open a terminal (by going to Applications, then Utilities, and then double clicking “Terminal”) and enter the following command-line argument (don’t type the “$”)

$ python -V

it should display in Terminal something like the following:


If it says 2.6 or 2.7 (possibly with a following number like 2.7.1), you’re okay. If it says 2.4 or 2.5, go to and download a newer version. Multiple versions of Python can exist on a single computer without any problems.

Download music21

Download the most-recent music21 package by getting the first .tar.gz file from the following URL.

The newest version should be at the top. Do not download the -no-corpus version of the file.

Once it’s downloaded, double-click the icon on your desktop named something like music21-1.3.0.tar.gz – this will create a new directory on your desktop called something like “music21-1.3.0”. Look inside it.

You will see the following files:


If you’re with us so far, you’re halfway there.

Starting the Configuration Assistant

The music21 Configuration Assistant installs music21 in a place where Python can find it and lets you configure music21.

Double click on the installer.command file to start. This file should open a Terminal window and begin running the Configuration Assistant. As this is a program downloaded from the Internet, the System will likely warn you about running it. Go ahead and click “Open”.

After waiting a few moments to load modules, the Configuration Assistant begins.


The first option is to install music21 in its standard location (see below, The Installation Destination). Enter “y” or “yes”, or press return to accept the default of “yes”.

Before installation begins you may be asked for your Mac password. (The cursor won’t move or display any letters when you type in the password. Just rest assured that the characters are being transmitted). As Python packages are stored in a System directory, you need to give permission to write files to that location.

(If you don’t get a prompt but instead start getting a lot of errors, you probably do not have an administrator account on your Mac. To make yourself one, quit the installation program (just close the window), open System Preferences from the Apple menu in the upper left corner of your screen, click on Users and Groups (4th Row). Click on the lock on the lower-left corner – you’ll need your Mac password. Then click “Allow user to administer this computer”. Then close System Preferences and click the music21 installer.command button again and go back one step.)

During installation, a large amount of text will display showing files being copied. Sorry about the mess. Just ignore it! It means it’s working.


After installation the Configuration Assistant will try to configure your setup. If you have never used music21 before, following these prompts is recommended.

Selecting a MusicXML reader is the first step. MusicXML is one of many display formats used by music21, and will provide an easy way for you to visualize, print, and transfer the music you edit or develop in music21.

The Configuration Assistant will attempt to find a MusicXML reader on your system. If it can’t find any, you will be asked to open a URL to download Finale Notepad 2012, a simple and free MusicXML reader and easy writer. Installing this reader is recommended for users who do not have Finale, Sibelius, MuseScore, or another MusicXML reader. You might want to try MuseScore instead, which is also free and doesn’t require you to register to download it.

If one or more MusicXML readers are found, skip ahead to the next instructions.


If you choose to install Finale Notepad (formerly Finale Reader; hence the pictures below), you will download an installer. Launch the installer immediately, and follow the instructions.


After installing a MusicXML reader, or if you already have one or more installed, the Configuration Assistant will present you with a list of MusicXML readers from which to select one to use with music21 by default. This means that music21 will attempt to open MusicXML files with this application. This setting can be easily changed later. Enter the number of the selection as presented in the list:


After selecting a MusicXML reader, you will be asked a number of questions about working with music21. They concern whether music21 can access the Internet, and whether you are willing to comply with the license for use of music21 and the included corpus of scores. You have to accept the license to continue (we need to retain some rights you know!), but you don’t have to give us access to the Internet.


After the Configuration Assistant is complete, you can close the window when it says “[process terminated]”.

After Installation

CONGRATS! You’re done with installing. You can delete the music21-1.3.0.tar.gz file and music21-1.3.0 folder from your desktop now.

Open up the Mac Terminal (under Applications/Utilities/Terminal). You might want to drag it to the dock. You’ll use it often.

After a successful installation, you may proceed to usersGuide_01_Installing to begin using music21.

Installation Help

If you have followed all the instructions and still encounter problems, start over from scratch and try it again very carefully. If you still have problems contact the music21 group and someone should be able to help: