After upgrading Mojave to Catalina I discovered my Macintosh HD was split into 2 partitions:
I tried searching for some info on the web and didn't find anything useful. Some posts on Reddit about the Beta version of Catalina. But I got the upgrade from the official release.
So, for now, I decided to return to Mojave and to search for more info about this case. Any assist here?
iMac Line (2012 and Later)
Same thread just select All Replies, page 2. But to help now, I copied and pasted the whole reply. Print the instructions and take your time:
"Last week I upgraded to Catalina and because of Catalina problems, I restored Mojave 10.14.6 successfuly from my Time Machine backup. During the process, I too wound up with the " Mac HD - Data" in Disk Utility and my used space more than doubled. It annoyed me that Catalina could force someone to buy larger external drives for backups or worse, have to buy a new computer. I spoke to a Senior Tech at Apple this AM and my disk is back to normal. Here are the steps involved - BE CAREFUL. If unsure, leave well enough alone.
1) Back up computer (!) even though it will take a long time
2) Shut Down Mac (not restart)
3) Start Mac - immediately hold down the CMD-R keys
4) When the Apple logo appears and you see the progress bar, release the keys
5) You will see eventually the MacOS Utilities screen
6) If you cannot move the arrow, use a USB WIRED Mouse (a real possibility)
7) Select Disk Utility and then Continue
8) Select "Macintosh HD - Data" DO NOT select ERASE. Please - be careful!
9) Upper menu bar of your Mac - click Edit
10) Select "APFS Volume Macintosh HD - Data" (careful - make sure of what you select) & Click 'Delete'
11) When all finished, go to upper menu bar of your Mac and select Restart
12) After you have restarted, check Disk Utility to make sure Mac HD-Data is really gone
What caused an additional mess for me was doing the Security Update 2019-002. Apple is working on a fix to prevent the Mac from freezing when installing this Security Update as other Mac users have the same problem.
Again CAUTION! Do NOT delete "Macintosh HD". Make sure you select "Macintosh HD - Data". If feeling queasy about any of this, do NOT do it. After I had performed this process, I asked the tech to repeat everything to me and I wrote it down and reconfirmed. BTW, my disk is normal now, Mojave works great. I do not need to buy larger capacity hard drives for backups.
Good luck!"
Hello all, when restoring to factory settings, and having already backed up my data should I be erasing both partitions of the internal hard drive ? Ie Macintosh HD AND Macintosh HD - Data to free up space on my HD? Thank you
SamuelComerford wrote:
Hello all, when restoring to factory settings, and having already backed up my data should I be erasing both partitions of the internal hard drive ? Ie Macintosh HD AND Macintosh HD - Data to free up space on my HD? Thank you
Hi there,
If you want to keep your files you can follow these instructions: https://support.apple.com/en-us/HT204904
If instead you want to completely erase your disk, this must be carefully done. There are two steps, related to the two volumes ("disks"). Follow this: https://support.apple.com/en-us/HT208496
Hope it helps
TM
Thanks for sharing. I'll sit here and ponder the relevance of that, but thanks for sharing anyway.
So when cloning the internal drive to a bootable external drive I should choose Macintosh HD - Data?
You would need both, cloned into an APFS file format with them both in the same container.
I don't know what cloning software will accomplish that.
How does this affect backups with say Carbon Copy Cloner?
Do I need to back up both to retain a bootable copy?
Have you read any of the posts in the thread? Several of which refer directly to backing up with Carbon Copy Cloner. For instance, the one just above yours?
Hi Terence. 🤔
Can you throw any light on my query here, please? https://discussions.apple.com/thread/250781327
I've come to a bit of an impasse. I'd appreciate your view.
TIA
Thank you for this explanation. It's what I needed explained!
And if I want to erase the disk and make a clean install? What do I do with these partitions?
Thank you snowmill. Worked perfectly.
Thanks Old Toad. You nailed it for me.
Many thanks for that information. That was extremely helpful. Happy New Year. Sam
Many thanks for that. That response was really appreciated
Hello there! Can you explain what your solution was? You cloned the -Data drive in Disk Utility?
Macintosh HD - Data: what is that?
