After installing Catalina a second time, it put a second Mac HD data partition. Then when trying to use Time Machine, it failed. Because there are two drives with the same name HD data. How do I rename the drive or delete the Drive. How do I know which one Catalina is using?
iMac Line (2012 and Later)
I had this after doing a recovery. Here's how I fixed it, WITHOUT going into recovery mode (although that is the proper way to do this):
Note that before I tried this, I just ejected the volume and emptied the trash thinking it would work like the old .dmg install mounts, but upon restarting lo and behold there it appeared.
Hope that helped give an easy way to end the suffering!
Chris.
Just adding that the second data drive on the desk top is the extra. I renamed it so I could tell the difference in disk utility when in recovery mode . I removed it and then restarted. No need to wipe the drive and perform a reinstall of the system.
To remove the redundant “Macintosh HD data” before a fresh Catalina install:
In recovery mode disk utility there is the VOLUME + - in the top of the box. Select your “Macintosh HD data” and then click -
This will delete it.
Launch Disk Utility, take a screenshot of the sidebar and post. Like this:
The computer has to be totally erased and Catalina downloaded from internet recovery mode.
I would only use the last back up; the back up that only contains one drive. However, you can use the finder to change the name of one of the HD data drives. Allowing time machine to back up. This only changes the name that YOU see. Not the name that Catalina is actually using for its HD data.
of course, the risk is: you are copying the same problem and inserting it after you have cleaned everything up. Especially, if you look at the HD data drive and it has already created a new container and or volume.
do you not have a good back up before the problem started?
copying the problem, will most likely create another problem.
Apple has confirmed, that renaming the drive just exacerbates problems.
basically, starting fresh, with an old back up, which was known to be good is useful.
to answer one of your questions: you can look up the time and date in finder through GET info, about when the drive was created.
The main reason, I had to start over was: each data drive had created another volume and container, which doubled the memory usage. The easiest way is to remove everything off the computer, via the steps, and then repair with the backup before the problems. My iMac is working great and fast as advertised in Catalina.
I have the same issue. I named the second data partition ghost. And that's that. Look at the size. Mine is 1mb (go to time machine exclude the duplicate partition and it says how big it is). It's not a real partition.
My advice. Hide it and forget about it - unless you need that get that 1mb back. Probably it will get fixed in an update later on. Why risk your system or spend hours on a fresh install.
It's a ghost :-)
The -Data drive/volume is your working volume with your applications, home folder with its sub folders, etc. The other drive/volume is a read-only drive for the system and its files. It's Apple's next step in securing the system from outside miscreants.
I've rename named my volumes. The data volume is Toad Hall and the other is Catalina:
Just ignore the non-data volume.
This illustrates my case.
From the reply by craig150 it seems it happened when I downloaded Catalina from the Mac App Store to create a backup bootable USB installation drive. It looks like the data volume being used is the one at the bottom, but no idea what to do to revert to normal, other than re-formatting the HD again.
Answering to myself (hope it helps):
Catalina is installed on a dedicated read-only system volume, while your files and data are stored separately in another volume labelled with the suffix "- Data."
The idea behind this setup is that it helps prevent the accidental overwriting of critical operating system files, since the user can no longer alter data or store files on the read-only system volume.
In practice, the average user shouldn't notice any difference after the split, since both volumes appear in Finder as a single unified volume.
In recovery mode you should see the option to restore from time machine on the menu. Just plug in your time machine HD and select it as the drive to restore from. The computer does the rest.
Try running Disk Utility's First Aid on the TM drive. Then try another backup.
This has 3 drives. 2 are data drives. I suspect it added the 3rd one when I reinstalled. Still trying to figure out if I can delete it, without any consequences or rename it. I am not sure I want to rename something that I don’t need
OS Catalina. 2 MAC HD data drives
