Trying to increase the size of my hard drive, Error: -69771: The target disk is too small for this operation

Solution 1:

I have to quit applications because there is not enough free memory

Free memory is not hard disk space, but rather RAM. You can resolve this by quitting apps that are using lots of memory. You can find which processes are using memory in Activity Monitor.

If you're still interested in making more disk space for other reasons…

a gap is required in your partition map which is missing or too small

This is the actual error. diskutil list shows an APFS container disk0s2 of 70 GB, and a HFS partition disk0s3 of 180 GB.

70 GB + 180 GB = 250 GB, which is the total size of your disk — there's no free space gap to resize your container into, it's as big as it can be.

You can remove your HFS partition disk0s3 (back up your data first), then expand your APFS container into the gap created by that operation.

Solution 2:

You’ll need to remove your HFS+ partition (disk0s3) in order to expand your APFS container (disk0s2), since the APFS partition is constrained on both sides.

The method to do so will depend on how full the HFS partition is.

Easiest solution:

1. copy any data off of your HFS+ partition to an external hard drive
2. delete the HFS+ partition
3. enlarge your APFS container (disk0s2) as desired, then enlarge the APFS data volume as required - (be sure to leave at least enough free space at the end of the disk for the next step)
4. create a new HFS+ partition in any space that now remains, if desired, and copy back the data you removed in step one

If you don’t have an external drive handy, and the HFS+ partition is less than half-full:

1. Shrink the HFS+ partition as much as Disk Utility will allow (but don’t make it smaller than the amount of space you want to add to the APFS container)
2. Create a second HFS+ partition in the newly free space at the end of the disk.
3. Copy all files you wish to keep from the first HFS+ partition to the second (new) HFS+ partition. You can do this in the Finder, via the command line, or with a tool such as Carbon Copy Cloner or SuperDuper!
4. Delete the original HFS+ partition and rename the remaining HFS+ partition as desired. Now your disk will have a block of free space between the APFS container and the HFS+ partition
5. Use Disk Utility (or terminal commands) to increase the size of the APFS container (disk0s2) and then the APFS volume (“Macintosh HD - Data”, I presume, in your case) as needed.

Note to others:

There is another time you will get “insufficient space” errors when trying to modify or add partitions: often on external USB hard drives that still have their factory formatting, the EFI partition is either missing or too small for macOS.

Microsoft recommends it be at least 100 MB, but macOS requires a larger size (200 MB, I believe).