Time Machine not recognizing Mac's backup database

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Level 2

176 points

Time Machine not recognizing Mac's backup database

How can I tell Time Machine "This is the backup I want to use for this machine"?

In brief:

When I try to backup my Mac Pro to its Backup.backupdb folder on the same volume it has always been using, Time Machine does not recognize the backup as belonging to that machine. The drive icon shows up as a Time Machine drive in the Finder, but when I select it as the backup drive, it shows the Oldest and Latest backups as "None". This began when I moved the .sparsebundle from another Mac that had been backing up to the same volume (separate databases, same volume, bad idea).

Background and details:

I'm have a Backup.backupdb folder on an external volume directly connected via Thunderbolt to which I've been backing up my Mac Pro with no problems. That volume was originally the Time Machine backup drive for a MacBook Air, which was concurrently maintaining a .sparsebundle file on the same volume but was completely separate. I added the Mac Pro's backup to that drive temporarily so I could shuffle things around and make discreet volumes for the different backups. This was obviously a bad move, but it worked fine—until I wanted to put each backup on its own volume.

Time Machine was keeping the MBA backup in the usual .sparsebundle. When I first chose the same volume for the the MP backup, Time Machine made a Backup.backupdb folder for it, and every time I'd start a backup, Time Machine would ask if I wanted to inherit the other backup or keep them separate, and I kept them separate. The .sparsebundle from the MBA is now on a new volume and is working as expected, but I'm getting no joy when I try to get the MP to backup (see brief, above). Here's what I've tried:

Moving the Time Machine pref file, but that doesn't seem to be where Time Machine stores its settings because all of my exclusions, etc. were still intact.
Copying the Backup.backupdb to another volume by following Apple's instructions for moving a local Time Machine backup. The Finder will keep copying the 250 GB folder until it fills a 1 TB volume.
Creating an archive of the Backup.backupdb. Keka will get stuck preparing the operation. I've let it run for up to 24 hours.
Using Disk Utility to create a disk image from the folder. This runs indefinitely with no progress.

I originally posted about it in the thread below, but the problem has changed from "Finder not copying" to How can I tell Time Machine "This is the backup I want to use for this machine"? (Finder still won't copy it, but I don't actually need it to move—just work!

https://discussions.apple.com/thread/251684759?login=true&page=1

There are two things I can think of to try:

Now that it's by itself on that volume, Disk Utility's "Restore" might restore the volume to a .sparsebundle that Time Machine will recognize.
Connect the volume to another Mac and mount it over a network. Time Machine stores non-local backups as a Backup.backupdb folder instead of a .sparsebundle. Maybe it will associate the backup and machine that way and then I can somehow salvage the backup. (?)

I'd really love some direction before I do any more failed experiments. I have physical disabilities that make all the recabling between 3 Macs plus accessories a big challenge on top of the downtime it takes to run one of these tests for Apple. I'm sure there's a single command or three line shell script that will resolve this. I'd love to find it!

Mac Pro

Posted on Aug 25, 2020 12:25 AM

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Answer 1

Aug 25, 2020 7:14 AM in response to Glen Schuler

Glen Schuler wrote:

How can I tell Time Machine "This is the backup I want to use for this machine"?1.

In brief:

Backup disks you can use with Time Machine - Apple Support

https://support.apple.com/en-us/HT202784

How to use Time Machine to back up.. your Mac: https://support.apple.com/en-us/HT201250

I will add that Time Machine is great when it works as advertised, not so much when it does not.

3-2-1 Backup Strategy: three copies of your data, two different methods, and one offsite.

—Boot clone https://discussions.apple.com/docs/DOC-10081

—How to use Time Machine to back up or restore your Mac: https://support.apple.com/en-us/HT201250

—Use DiskUtility Restore feature https://support.apple.com/guide/disk-utility/restore-a-disk-dskutl14062/mac

note: >System Preferences>Security & Privacy >Privacy>Full Disk Access

unlock the padlock, press the + button and add Disk Utility

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Answer 2

John Galt

Level 10

145,928 points

Aug 25, 2020 8:35 AM in response to Glen Schuler

I'm sure there's a single command or three line shell script that will resolve this. I'd love to find it!

There might be. If the suggestion I had for you in your other Discussion (remove and then subsequently re-add that backup in TM's Preferences) does not work, you can use the tmutil inheritbackup command. That will give you a chance to rectify the choice you made earlier: "...every time I'd start a backup, Time Machine would ask if I wanted to inherit the other backup or keep them separate, and I kept them separate."

In Terminal, type man tmutil for specific details.

In the end though you might find Barney-15E's suggestion worth considering, and I agree with it. It's far more important to have a current, constantly updating backup than it is to retain backups from long ago. And, if there is something you desperately need from that backup, restore it now. You did not indicate if that is a factor in your reluctance to simply erase and start a new set but if it is please ask. To access backups from a TM backup not accessible from the "Enter Time Machine" interface, merely hold an option key when clicking the TM icon and choose Browse Other Backup Disks..."

I haven't commented on "keka" but mostly because I don't know what it is, besides, if you can't do something with DU or asr or tmutil or any number of other macOS-specific Unix commands then you won't be able to do it with anything else either.

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Answer 3

Glen Schuler Author

Level 2

176 points

Aug 30, 2020 9:19 PM in response to John Galt

There might be. If the suggestion I had for you in your other Discussion (remove and then subsequently re-add that backup in TM's Preferences) does not work, you can use the tmutil inheritbackup command. That will give you a chance to rectify the choice you made earlier: "...every time I'd start a backup, Time Machine would ask if I wanted to inherit the other backup or keep them separate, and I kept them separate."

I need to find a way to make this clear because there's misunderstanding that I think is inhibiting a solution. The two backups were always separate. Two machines, two completely different backups. Never have the twain met except that they were on the same volume. There was never, ever, at any time, a point when they were one, and I want to continue to maintain them as separate backups. I'm not rectifying anything—just asking for a simple behavior change from Time Machine.

In Terminal, type man tmutil for specific details.

This is what I'm looking for! So, inheritbackup and associatedisk -a pointed to the folder with the machine's name (the only one there) inside the "Latest" give me about 20 similar errors. They're all the same, just different numbers:

objc[6508]: Class SLWebTokenHandlerController is implemented in both /System/Library/Frameworks/Social.framework/Versions/A/Social (0x12b8f2820) and /System/Library/PrivateFrameworks/SocialServices.framework/Versions/A/SocialServices (0x12b876268). One of the two will be used. Which one is undefined.

This seems like something that can be fixed! Any ideas?

In the end though you might find Barney-15E's suggestion worth considering, and I agree with it. It's far more important to have a current, constantly updating backup than it is to retain backups from long ago. And, if there is something you desperately need from that backup, restore it now.

Believe me, I've been tempted to just bail on the backup, but you don't know what you need until you need it, you know? And while there's no hot emergency on this machine at the moment, I'd like to know how to rectify this problem in the event it occurs again.

haven't commented on "keka" but mostly because I don't know what it is

Keka is an excellent and free file compression utility. I highly recommend it. Off topic, but the .7z archives on the slowest setting are sometimes a quarter of the size of that other compression utilities produce, even on files you wouldn't think could compress much more. Plus, it plays nice with all OSes/file systems.

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Answer 4

John Galt

Level 10

145,928 points

Aug 31, 2020 11:05 AM in response to Glen Schuler

Never have the twain met except that they were on the same volume.

I really have to apologize, because I thought I understood what you wanted to do, then I realized I misunderstood, then I thought I understood again. With that comment, now I'm back to what I originally thought—they're on the same volume!

Along the way, something became seriously messed up with that. With all my permutations and combinations of TM backups never once have I attempted to maintain network-hosted backups and locally hosted backups on the same volume. Forget about understanding someone else's troubles; I would have enough of my own if I tried to do that. In fact in the course of researching your question I repurposed one of my TM backup disks in an effort to determine if I can duplicate what's going on with your installation. It's been backing up and encrypting for the past couple days. After it finishes, if I come up with any additional suggestions I'll let you know.

I also have to confess a personal bias against becoming emotionally attached to backups, which is the reason I stated my agreement with Barney-15E's practical solution. I appreciate the challenges you're facing and sincerely enjoy solving problems but in the end I'm a pragmatist: I don't know if it's possible to unscramble this egg. I wish I could be more helpful.

Keka is an excellent and free file compression utility. I highly recommend it. Off topic, but the .7z archives on the slowest setting are sometimes a quarter of the size of that other compression utilities produce, even on files you wouldn't think could compress much more. Plus, it plays nice with all OSes/file systems.

Thank you for that recommendation. The .7z utility I had been using is no longer supported so I'll consider that one. It looks good.

It seems I learned more from this Discussion than you did 🤪

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Answer 5

BDAqua

Level 10

244,949 points

Aug 31, 2020 2:02 PM in response to Glen Schuler

One of the two will be used. Which one is undefined.

I'd ignore that, I'm not sure but Console logs are pretty worthless, & I think yjat particular line was just a leftover breakpoint or milepost from programming/debugging.tracing.

The one & only time I needed TM it failed completely, now I only use it in a attempt to help with it, I use it but rely on Carbon Copy Cloner...

http://www.bombich.com/software/ccc.html

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Answer 6

Barney-15E

Level 10

116,074 points

Aug 25, 2020 5:14 AM in response to Glen Schuler

I'd erase the volume and start a new backup on that drive.

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Answer 7

Glen Schuler Author

Level 2

176 points

Aug 30, 2020 8:53 PM in response to leroydouglas

Thanks. I've already done all of the things mentioned in the articles you have linked. They are not working. And, Yes, I do follow that 3-2-1 strategy. It just sucks when something breaks!

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Time Machine not recognizing Mac's backup database

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