macOS H Sierra/Mojave

OrganAssist is maintained in my spare time. I will try to resolve any problems and am happy to attempt developing OrganAssist to support new manufacturers if necessary. Please use the Contact Page to give feedback or ask any questions.

macOS – High Sierra and Mojave only

OrganAssist should run on any Mac computer made from mid-2009 to mid-2019 provided it is running one of these versions of macOS.

*** IMPORTANT *** To run OrganAssist on macOS you will need to download both OrganAssist and also the OA Midi Helper application.  This is required to prevent MIDI data loss on input to OrganAssist.  Please see the User Manual for instructions on configuring your macOS setup.

Due to security measures in macOS , this application may NOT run if activated from the Downloads folder.  Move the application to your desktop or other location and use control + click to open it the first time.

Both applications are CodeSigned which means that macOS will validate the application and give a warning message if it has been damaged during the download. Downloading a second time should resolve any problems.


When OrganAssist is run for the FIRST time, the default language MUST be English.   If necessary, change the System Preferences, Language and Region, click + to add English and drag it to the top and restart the system.  Once OrganAssist has run ONCE successfully, you can reset your language and, when you restart your system, OrganAssist will continue to work.  If you have already run OrganAssist and had an “Error 53 File not Found” message then you must go to the folder ~/Library/Application Support and delete any folders starting com.organassist. before running OrganAssist with the language set to English.

Click on this button to download (Filesize: 230 MB)

Click on this button to download (Filesize: 3.4 MB)

macOS – Gatekeeper Security

If you have already run OrganAssist from the Download folder then this has created an invalid folder elsewhere that prevents OrganAssist from running permanently. To solve this problem you must go to your Home/Library/Application Support folder and delete any folder(s) starting with com.organassist (the name will include a random number). After deleting any com.organassist folders, move the application from Downloads to another location using Finder and then run it again.