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APFS Volume corrupted in Catalina and I can't reinstall OS

I have over 220Gb available on my 1Tb iMac Fusion drive. This is confirmed by About This Mac > Storage


However, the APFS seems to have got corrupted, because Finder windows and Disk Utility say that there is only 19.24Gb available. (This is the same in both normal and Safe Boot mode)


I had a long online chat with Apple and the advice was to boot using Cmd-R and reinstall Catalina. However, when I try this, it says there is not enough room to reinstall the OS, because it thinks there is only 19.24Gb available.


I have tried deleting more files, but it still says only 19.24 Gb available. So I'm completely stuck.


Help!


This is the sort of issue that Disk Warrior used to sort out in minutes, but it doesn't support APFS files :-(

iMac 21.5″ 4K, macOS 10.15

Posted on Jan 10, 2022 6:23 AM

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Question marked as Top-ranking reply

Posted on Jan 11, 2022 2:24 AM

I appreciate that these things are posted in good faith. However I indicated (or at least implied) in my original that points 2, 3, 4 and 6 had already been addressed before I posted. (If I know I have over 220Gb free, but it's only showing 19Gb, why would I be looking to 'see used and available storage space'? It was this showing incorrectly that was the problem!)


Earlier conversations with Apple had also covered point 1, although yes, I didn't say that.


In one's reply one did describe trying your suggestion 5 and the outcome. One doesn't know how much more exactly one could have described that? :-(


After a further long conversation with Apple with one of the higher level specialists, the only course of action was the nuclear option of completely erasing the iMac, then reinstalling the OS and all my files. Fortunately I back up to Time Machine every other day, but could have done without the time and hassle factor. But at least I have a functioning Mac again.

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4 replies
Question marked as Top-ranking reply

Jan 11, 2022 2:24 AM in response to PRP_53

I appreciate that these things are posted in good faith. However I indicated (or at least implied) in my original that points 2, 3, 4 and 6 had already been addressed before I posted. (If I know I have over 220Gb free, but it's only showing 19Gb, why would I be looking to 'see used and available storage space'? It was this showing incorrectly that was the problem!)


Earlier conversations with Apple had also covered point 1, although yes, I didn't say that.


In one's reply one did describe trying your suggestion 5 and the outcome. One doesn't know how much more exactly one could have described that? :-(


After a further long conversation with Apple with one of the higher level specialists, the only course of action was the nuclear option of completely erasing the iMac, then reinstalling the OS and all my files. Fortunately I back up to Time Machine every other day, but could have done without the time and hassle factor. But at least I have a functioning Mac again.

Jan 10, 2022 7:08 AM in response to BlueberryiMac

Start with


1 - Rebuild the Spotlight index on your Mac


2 - What is “Other” storage on a Mac, and how can I clean it out?


3 - Free up storage space on your Mac


4 - OmniDiskSweeper Safe to use


5 - How to delete Time Machine snapshots on your Mac


6 - See used and available storage space on your Mac


The final word from Apple on Managing the " Other " Category


Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.


Jan 10, 2022 7:45 AM in response to PRP_53

P. Phillips wrote:

Start with

1 - Rebuild the Spotlight index on your Mac

2 - What is “Other” storage on a Mac, and how can I clean it out?

3 - Free up storage space on your Mac

4 - OmniDiskSweeper Safe to use

5 - How to delete Time Machine snapshots on your Mac

6 - See used and available storage space on your Mac

I have already cleared over 200Gb of space on the 1Tb drive, as I mentioned in my OP (I've been using Macs since 1993, so I have a good handle on the basics!)


The problem is that the Mac thinks it only has 19Gb of free space whereas it has over 200Gb.


When I tried deleting the Time Machine snapshot, Terminal returned the message unable to write to /var/db/sudo/ts/(my user ID): No space left on device

APFS Volume corrupted in Catalina and I can't reinstall OS

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