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PMurphyB
User level: Level 1 (4 points)

Boot Camp stuck on 'Partitioning Disk' on 2020 iMac

I'm trying to run bootcamp on my 2020 iMac with 2TB of storage currently installed with Tahoe 26.6.2. I have been stuck on "Partitioning Disk" for two days now (I have left it overnight for two days) with no progress. Interestingly, my settings show that I now only have 1.5TB (I setup 500GB for Windows). I ran diskutil list and got these results:


/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         2.0 TB     disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.5 TB     disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            12.6 GB    disk1s1
   2:              APFS Snapshot com.apple.os.update-... 12.6 GB    disk1s1s1
   3:                APFS Volume Macintosh HD - Data     758.5 GB   disk1s2
   4:                APFS Volume Preboot                 2.8 GB     disk1s3
   5:                APFS Volume Recovery                1.5 GB     disk1s4
   6:                APFS Volume VM                      8.6 GB     disk1s5

Posted on Oct 13, 2026 8:50 AM

2 replies

WheelieNick
User level: Level 9 (74,110 points)

Oct 14, 2026 4:38 AM in response to PMurphyB

Because it has been stuck for two days with zero progress, it will not resolve itself.

  1. Press Option + Command + Escape.
  2. Select Boot Camp Assistant and click Force Quit.


And then you can try and do the process again to see if the issues persist

HWTech
User level: Level 9 (78,350 points)

Oct 14, 2026 12:33 PM in response to PMurphyB

It seems the Bootcamp Assistant partitioning tool did remove 500GB from your main macOS partition/Container, but never created a new partition for Windows.


You will likely need to merge the missing 500GB non-partition (aka free space) back into the APFS Container so you can start over again. Merging that 500GB of "free space" as Disk Utility calls it can sometimes be difficult and may even require the use of the Terminal command line. I did have instructions from several years ago on the Apple forum. First try @WheelieNick's suggestion with trying Bootcamp Assistant again, and if no luck then try merging that empty "free space" non-partition back into the APFS container using Disk Utility's "Partition" tab.

Originally posted at discussions.apple.com/thread/256375519