You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Dual boot Mojave-Catalina set up to try out Catalina. Now want to remove Mojave OS

I was running Mojave, but before installing Catalina I set up a dual boot to check that everything worked with Catalina. I'm not a tech expert so I was surprised how easy it was to create a new volume and install Catalina into it. I'm now content that Catalina works for me and runs the apps I was interested in so I now want to make the change completely.


But how do I now move to Catalina? I can find advice online how to set up a dual boot, but not on how, having done so, I can move to a single OS, in this case Catalina. I am looking for advice please


In System Preferences - Startup Disk are now shown two systems: "Catalina macOS 10.15.7" and "Macintosh HD macOS 10.14.6" (which contains the Mojave OS). I suspect simply deleting the "Mojave" Folder on my disk may cause problems, possibly serious ones.


I thought about using Disk Utility to delete both of the "Catalina" and "Catalina Data" volumes so I am left only with "Macintosh HD macOS 10.14.6" (i.e. the Mojave OS). Once deleted I would again install Catalina. Would this work? I want to keep things as simple as possible


If I can work this out then I will probably adopt the same approach for Big Sur in due course.


Hope someone can help.

iMac 27″ 5K, macOS 10.15

Posted on Nov 16, 2020 8:41 AM

Reply
Question marked as Top-ranking reply

Posted on Nov 17, 2020 9:45 PM

You should be able to just select and delete the Mojave APFS volume (or old-style partition). Or (erase it and) install Big Sur on it for testing. Or erase the whole device (not just the volumes under it) and make a clean install from scratch.


But make good backups before doing any of those. And I'd make sure to have another external disk that I can Option-boot from, just in case something goes totally wrong (there is Internet recovery but it is slow).

Similar questions

6 replies
Question marked as Top-ranking reply

Nov 17, 2020 9:45 PM in response to Crackerjack2012

You should be able to just select and delete the Mojave APFS volume (or old-style partition). Or (erase it and) install Big Sur on it for testing. Or erase the whole device (not just the volumes under it) and make a clean install from scratch.


But make good backups before doing any of those. And I'd make sure to have another external disk that I can Option-boot from, just in case something goes totally wrong (there is Internet recovery but it is slow).

Dual boot Mojave-Catalina set up to try out Catalina. Now want to remove Mojave OS

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.