If Notability is no longer launching on the Mac or you run into a "Notability" is damaged and can't be opened error, to get Notability working again, you'll have to completely remove Notability from the Mac and reinstall.
More specifically, all items associated with “com.gingerlabs.NotabilityMac” from the "~/Library/Containers" and the "~/Library/Preferences" folders need to be removed.
This guide has good manual directions: https://nektony.com/how-to-uninstall-apps-from-mac-completely
A third-party uninstaller app if you need help: https://apps.apple.com/us/app/cleanmymac-x/id1339170533?mt=12
Before doing so, please make sure that your notes are backed up in Notability’s native .note format. After reinstalling Notability, you can enable iCloud to have your library download again or re-import the notes from the backup.
A quick and easy way to create a backup on the Mac is to copy and paste your notes from the Notability Mac folder onto your hard drive:
Finding Notability's Folder on Mac
1. On your Mac, open the app named **Terminal**.
If you're not sure where to find this app, you can open it by searching for "Terminal" in Spotlight.
2. Paste one of these commands into Terminal:
If iCloud sync is off: open ~/Library/Containers/com.gingerlabs.NotabilityMac/Data/Library/Sessions
If iCloud sync is on: open ~/Library/Mobile\ Documents/ZP9ZJ4EF3S~com~gingerlabs~Notability
3. Press the keyboard's enter/return key.
For further assistance, please reach out to us!