I'm in the process of copying my TM backups to another volume. I followed these instructions: formatted the new volume, set the permissions, disabled automatic TM backup and dragged Backups.backupdb to the new volume.

That folder used about 400 GB on the old volume, and that was the estimated size shown in the copy status window. But then, after getting to 400 GB it just continued. Right now it is saying that 596 GB out of 596 GB have been copied and for the last few hours it's been showing that only 5 seconds are left. I've looked at Backups.backupdb on the new volume, which contains folders with different dates, and only 4 out of 15 folders have been copied so far! The new volume is 1TB, and all different tools report that 596 GB are indeed in use, so if it continues like this, there won't be enough space for my backup on the new volume.

How come is that possible? I suspect it has something to do with hard links that TM uses, but I got very strong impression that the above copy procedure described by Apple would make everything work automatically. What can I do? Should I cancel copying? I'm running macOS Mojave, and both volumes are formatted as HFS+ (Mac OS Extended).

  • Check the new disk is GUID not MBR. I'm not certain it makes a difference, but you can quit this copy, it will probably never complete in the space it has to work with. You're right in assuming it's copying a new 'real' version for every hard link it finds. – Tetsujin Aug 15 at 17:28
  • @Tetsujin It is GUID. I still find it hard to believe that Apple would recommend such a way of copying TM backup without even mentioning that the backup would grow 10x larger. – michau Aug 15 at 17:43
  • It shouldn't - but this isn't the first time I've heard of this happening, each time with Mojave… since the "off switch" vanished from TM prefs, to be replaced by only the "automatic" switch. It's not something I can easily test; my own TM is already 4TB & wouldn't fit anything else I have spare. – Tetsujin Aug 15 at 17:45
  • Just to tie these two seemingly related yet unanswered questions together in the side bar - see superuser.com/questions/1470443/… – Tetsujin Aug 17 at 9:46
  • I ran in into a similar problem in the past, but a Mojave patch some monhts ago suddenly fixed the issue for me, is your Mac fully patched? As a workaround, you could clone the drive and extend it as explained here: apple.stackexchange.com/questions/204462/…. – jaume Aug 19 at 8:26

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