Install or Upgrade

To install or upgrade MWorks on macOS, first download an installer disk image. Double click the disk image to mount it, then double click the MWorks.pkg icon to start the installer. The installer will guide you through the rest of the installation process.

If the installer detects an existing MWorks or MonkeyWorks installation, it will move all the existing components to a folder called MWorks Backup on your desktop. To remove this backup, simply drag the folder to the trash.

Uninstall or Revert

The MWorks installer disk image includes a script that will completely remove any current or legacy release of MWorks or MonkeyWorks from a macOS system.

To uninstall, open the disk image (.dmg file) you installed from (or download a more recent one), and double click the Uninstall MWorks icon. A terminal window will open, and you will be prompted to enter your macOS password. Once you do so, the uninstaller will move all MWorks components to a folder called Uninstalled MWorks in the trash. To permanently delete the uninstalled components, simply empty the trash.

If the uninstaller finds a previous MWorks version in the MWorks Backup folder on your desktop (which it will if you upgraded an existing MWorks installation and have not moved or deleted the backup), then after uninstalling the current version, it will re-install the old one. To uninstall the re-installed version, simply run Uninstall MWorks again.


To install MWorks on iOS, download it from the App Store. To uninstall, simply delete the MWorks application.


If this is your first time installing MWorks, or you are upgrading from MonkeyWorks, you will need to configure your installation before running experiments.


Configuration File

To configure MWorks, you assign values to a special set of system variables. The desired values are stored in a file called setup_variables.xml. On macOS, this file can reside in one of two directories:

  • For all users: /Library/Application Support/MWorks/Configuration

  • For a specific user: $HOME/Library/Application Support/MWorks/Configuration, where $HOME is the path to the user’s home directory (e.g. /Users/chris)

The user-specific configuration file takes precedence over the system-wide one, which allows individual users to customize their setup.

MWorks is distributed with two example configuration files, both of which are installed in /Library/Application Support/MWorks/Configuration/examples:

  • setup_variables_two_monitors.xml, appropriate for a two-monitor system where stimuli are displayed fullscreen on the secondary monitor

  • setup_variables_macbook.xml, appropriate for a laptop or other single-monitor system where stimuli are displayed in a non-fullscreen window

To use either of these examples, you must copy the file to one of the aforementioned directories and rename it setup_variables.xml.

During installation, the MWorks installer checks for an existing configuration file. If none is found, it installs a copy of setup_variables_macbook.xml for system-wide use.

Changing Configuration Options

The easiest way to modify configuration variables and save the changes to the configuration file is via MWServer’s preferences window, which provides a graphical interface to all settings controlled by setup_variables.xml. Configuration changes made via the preferences window are stored in the user-specific configuration file.

Alternatively, since the configuration file is an XML document, it can be edited with any text editor (TextEdit, Emacs, Vim, etc.).


To configure MWorks for iOS, use the system Settings app. You can find all of MWorks’ settings in the section titled “MWorks”.

The iOS version of MWorks supports most of the configuration options available in the macOS version. At a minimum, you should change the display width, height, and distance parameters to match your device and experimental setup. If you leave the server name blank, MWorks will use the device name specified in Settings → General → About → Name.