Reclaim free space

Question

Reclaim free space

I have a 1TB SSD in my iMac where I tested OSX 12.7.1 on a second partition.

Since everything is working fine I want to remove the old partition and use it for the new OSX.

This is where things went wrong. Merging, reclaiming, .... nothing seems to work.

How do I reclaim the 879GB free space?

% diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
                    (free space)                         879.3 GB   -
   2:                 Apple_Boot Recovery HD             650.0 MB   disk0s2
   3:                 Apple_APFS Container disk1         119.9 GB   disk0s3

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +119.9 GB   disk1
                                 Physical Store disk0s3
   1:                APFS Volume Dual OSX - Gegevens     89.4 GB    disk1s1
   2:                APFS Volume Preboot                 271.5 MB   disk1s2
   3:                APFS Volume Recovery                1.1 GB     disk1s3
   4:                APFS Volume VM                      1.1 MB     disk1s4
   5:                APFS Volume Dual OSX                15.6 GB    disk1s5
   6:              APFS Snapshot com.apple.bless.63E5... 15.6 GB    disk1s5s1

iMac, macOS 12.7

Posted on Nov 25, 2023 6:22 AM

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Answer 1

Top-ranking reply

MartinR

Level 7

24,312 points

Nov 25, 2023 11:33 AM in response to Tripple_Delta

I believe you need to boot into Recovery Mode and run Disk Utility from there. Assuming the free space is actually an unnamed Partition, you would remove that partition, then expand Container disk 1 to the full extent of the drive. If it's just free space (not a separate partition) you would only need to expand Container disk 1.

Important note. Use the Partition button in DU. Check the disk layout carefully. You can only expand Container disk 1 into the free space if the free space is "after" Container disk 1. If it's "before" Container disk 1 they can't be merged. You would have to wipe the drive, repartition and reinstall macOS.

I suggest doing a screenshot of the disk layout and post it here for further input before you attempt any changes to the disk.

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Answer 2

MartinR

Level 7

24,312 points

Nov 25, 2023 11:38 AM in response to MartinR

Corrected/expanded Important notes.

In DU, select View All Devices. Select the topmost device (it will be named something like APPLE SSD SM1024G Media). Then use the Partition button. Check the disk layout carefully. You can only expand Container disk 1 into the free space if the free space is "after" Container disk 1. If it's "before" Container disk 1 they can't be merged. You would have to wipe the drive, repartition and reinstall macOS.

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Answer 3

Nov 26, 2023 2:29 AM in response to MartinR

Free space is before container since there was the old and first OSX. Starting from scratch will be the only solution.

Thanks.

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Answer 4

HWTech

Level 9

69,182 points

Nov 25, 2023 5:07 PM in response to Tripple_Delta

FYI, in the future do not partition your drive....that is always a bad idea with most people realizing later that one or both partitions are too small. Most times it ends up in the situation you find yourself now where you must erase the drive and start completely over. I don't even recommend partitioning a data only drive for the same reasons.

With the APFS file system, you can just add a new APFS volume which sort of acts like a partition, but does not require resizing the partitions so it is much less risky. The new APFS volume will be part of the same hidden APFS Container so the two macOS installations will share the same storage pool, but they will still be completely separate since they reside within their own Volume Group. The APFS Containers are very complex. Basically you have the APFS Container which acts like a partition, but allows sub volumes to share the storage pool. Within the Container are now Volume Groups which house a full installation of macOS with multiple APFS volumes (root/system, Data, Recovery, VM (Virtual Memory), Update and APFS snapshots, and perhaps some other system related APFS volumes). Apple tries to hide most of this from the user even within Disk Utility, although you may be able to view portions of the drive layout.....on Apple Silicon Macs Disk Utility hides other hidden APFS Containers used by the system usually prior to booting into macOS.

Add, delete, or erase APFS volumes in Disk Utility on Mac - Apple Support

About the read-only system volume in macOS Catalina or later - Apple Support

Signed system volume security in iOS, iPadOS, and macOS - Apple Support

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