How to merge APFS partitions or move macOS installation

Question

How to merge APFS partitions or move macOS installation

I currently have my hard drive partitioned:

NAME FORMAT SIZE

MacIntosh HD APFS 3TB

Partition APFS(Encrypted). 1 TB

During a restore process, I was forced to install a new MacOS on the Partition Drive (wasn't allowing on the primary for some security reason?). I was able to get everything working, however the 1TB filled up quickly. I would like to merge the drives together into ONE if possible. If not, I would either move the OS onto the 3TB drive instead of the 1tb. Also it appears that I have duplicate folders. VERY LARGE duplicate folders. LIBRARY, USER, APPLICATIONS, SYSTEM.

iMac (2017 – 2020)

Posted on Nov 18, 2025 7:10 PM

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Answer 1

Top-ranking reply

D.I. Johnson

Level 7

32,153 points

Nov 18, 2025 9:04 PM in response to barefootchris63

While there is no easy way to "merge" two APFS volumes and preserve the data of each on a single volume, there is no need to repartition the drive to be rid of extra APFS volumes. Decide which APFS volume you wish to live without, copy the data from that to a backup drive or to another APFS volume, and then simply delete that APFS volume using Disk Utility.

The beauty of the APFS format is the ease with which APFS volumes may be added or subtracted from the APFS container on the drive. The total capacity of the drive will, by default, be made available to all of one or many APFS volumes within the container on that drive.

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

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Answer 2

HWTech

Level 9

68,432 points

Nov 19, 2025 9:31 AM in response to barefootchris63

If you partitioned the drive which seems likely since you have run out of space, then you will need to erase the computer & start completely over unless you can figure out the original issue with your original APFS Container/volume.

Erase your Mac and reset it to factory settings - Apple Support

If it is just another APFS volume, then perhaps you enabled a "Quota" on it to restrict its size.

FYI, I never recommend using multiple partitions due to this exact issue which almost always comes up.

Also, we have no idea of the actual drive layout. Use the following Terminal command to get a clear view of the internal drive's layout:

diskutil  list  internal

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