Indesign 2020 not opening. The older version does

What exactly do you mean with will not work? If you doubble click on the InDesign 2020 application icon inside the folder Adobe InDesign 2020 located in the Apps folder of your HD? Or do you mean that if you double click on a document it then opens in the older version? That second method is not considered good practice by the way, if  you have several versions installed it is better to open the App first and the choose File / Open to select the document. If however you still prefer to open the correct Application by double clicking a document, then change the file and app association in the Mac Finder: select a document, choose Show Info in the Finder, select Open with, then select your preferred version and make sure to Apply to All is set.

Hi there,

Thanks for reaching out. You can install multiple versions of Adobe app on OS. If you are launching the app from the launchpad then probably you have old version pinned there.

If you just want to use the latest version, you can uninstall the old version. Follow instructions on https://helpx.adobe.com/creative-cloud/help/uninstall-remove-app.html to do that.

Hope it helps.

Regards,

Ashutosh