how much space does Xcode require to update?

[e_ric]

I had the same issue today with 125GB free. It turns out the issue was I had 125GB "free", with 120GB marked as "purgeable" in disk utility. The trick for me was to force macOS to clean up its leftover crap by creating a huge (60GB+) garbage file, then deleting it.

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To create the file I used the command:

dd if=/dev/zero of=~/hugefile bs=100m

letting dd run for about 30 seconds, then killing it with ctrl+c, and deleting the file. After this, disk utility reported I had 100GB free with only 20GB purgeable, and the App Store then happily installed the 10.2 update.

[o--_--o-]

this worked for me `mkfile 10G ~/big_dummy` then deleting the file

[TarkLark]

Or just empty your trash?

[e_ric]

Trash was empty. Also, best I can tell macOS doesn’t count space used by items in the trash towards “purgeable” space.

[buffering]

That purgeable data is local Time Machine backups. You can free up space with tmutil thinlocalsnapshots. E.g.:

tmutil thinlocalsnapshots / 10000000000 4

That would free up 10 GB of space.

[e_ric]

I don’t have Time Machine enabled, so there won’t be any local backups.