I have a iMac 27" late 2012 that has automatically updated with macOS Catalina 10.15.7. The result is that many apps and functions do not work properly. How can I resolve this and is there an option to revert to an earlier version of the software?
iMac Pro
None of your 32-bit applications or 64-bit applications with 32-bit dependencies are supported in Catalina. Apple made this clear beginning in early 2014 with macOS High Sierra (10.13.4). There is no solution to run 32-bit applications on Catalina. Backup Catalina to a separate Time Machine drive (unless it has been backing up to your previous Time Machine drive), and set that aside.
If you had a last Time Machine backup from your prior version of macOS and set that drive aside so Catalina would not backup on that drive, then you may have the means to return to the prior operating system without losing your applications or personal data and settings. In that case alone, you would boot the Mac into Recovery and select Restore from a Time Machine backup. That would wipe the Catalina disk and then repave the older operating system installation from Time Machine. Maybe.
If Catalina has been backing up to that previous Time Machine drive, then you will not be able to return to your prior operating system without losing your applications and data. If you do have a standalone Catalina Time Machine drive now from the first paragraph, you can perform a clean installation of your prior operating system and during that initial setup process, have that Catalina TM drive mounted when it asks if you want to migrate from a Time Machine drive. If you are living right, that should retrieve your personal data and settings from Catalina.
None of your 32-bit applications or 64-bit applications with 32-bit dependencies are supported in Catalina. Apple made this clear beginning in early 2014 with macOS High Sierra (10.13.4). There is no solution to run 32-bit applications on Catalina. Backup Catalina to a separate Time Machine drive (unless it has been backing up to your previous Time Machine drive), and set that aside.
If you had a last Time Machine backup from your prior version of macOS and set that drive aside so Catalina would not backup on that drive, then you may have the means to return to the prior operating system without losing your applications or personal data and settings. In that case alone, you would boot the Mac into Recovery and select Restore from a Time Machine backup. That would wipe the Catalina disk and then repave the older operating system installation from Time Machine. Maybe.
If Catalina has been backing up to that previous Time Machine drive, then you will not be able to return to your prior operating system without losing your applications and data. If you do have a standalone Catalina Time Machine drive now from the first paragraph, you can perform a clean installation of your prior operating system and during that initial setup process, have that Catalina TM drive mounted when it asks if you want to migrate from a Time Machine drive. If you are living right, that should retrieve your personal data and settings from Catalina.
macOS 10.15.7 compatibility with iMac
