Time Machine Goes Back to the Future and Backup through Airport (BUG)

[G4R2]

I guess my Time Machine went forward in time and gave itself an upgrade to a future version by giving itself the ability to backup to an Airport Disk.

Kidding aside, this is a confusing little bug that I thought someone here might have some experience in solving.

The situation is that I backed up my hard drive using TM on Friday by plugging an external drive into my Macbook. It's an unwieldy solution so I moved my backup drive back to the Airport Extreme and figured that I would just have to move my Macbook there when I needed to do a backup. I did not expect Time Machine to work in any fashion over the Airport connection with the external drive.

Last night I turned on the external drive for an unrelated reason and left it running for a little while. When I went to my Macbook I was surprised to find that it was backing up to Time Machine over the wireless network!

Great- Except it's a bug of some kind. It was backing up to the external disk but it wasn't backing up correctly. Instead, TM had mounted a diskimage of the backup destination on my desktop with the corresponding file in the root directory of my external drive. Moreover, it was backing up my entire volume again, disregarding the previous backup.

So I cancelled the backup (as it would likely take a long time to do a backup and fill up my external drive with duplicate files) and decided to plug in the drive into my Macbook again.

The drive was recognized as a TM drive but once again it mounted a disk image on my desktop, began to backup the entire drive rather than just the altered files, and created an archive in the root directory of the external drive.

Anyone have a clue as to what is happening and how to correct this odd behavior?

 

[REBELinBLUE]

Seems that this is how it is suppose to work

https://forums.macrumors.com/threads/375896/

 

[G4R2]

Seems that this is how it is suppose to work

https://forums.macrumors.com/threads/375896/

Thanks- That may explain the behavior that is occurring over the Airport.

However I'm still confused why this would occur again when I replug the external drive directly back to my Macbook through USB. Time Machine at this point ignores the previous backup and reverts to this behavior of creating a disk image. Perhaps when I plugged the external drive to my Airport it remapped the hardlinks so that when I plug it into my Macbook the computer thinks it is on the network? It's not the type of behavior I would have expected.

 

[REBELinBLUE]

I'd imagine it sticks to creating the disk image because that is where time machines settings is telling it to backup to. That makes sense IMHO because if it were to then backup to the normal location and you then moved it back to the network I'd imagine it would have problems in that it won't only use the disk image. I'm willing to bet that if you activate time machine when the drive is on the network you will only get the backups in the disk image, not the ones in the backup folder.

 

[G4R2]

I'd imagine it sticks to creating the disk image because that is where time machines settings is telling it to backup to. That makes sense IMHO because if it were to then backup to the normal location and you then moved it back to the network I'd imagine it would have problems in that it won't only use the disk image. I'm willing to bet that if you activate time machine when the drive is on the network you will only get the backups in the disk image, not the ones in the backup folder.

Thanks again. That's very informative and makes sense.