Time Machine can't Read Entire Archive

[DonP]

I have a 2TB Time Machine HD backing up 165GB from my iMac running Mojave.

If I "Enter Time Machine" I see the cascading windows indexed back to 12/29/17 which is when I started Time Machine.
But I'm only able to bring up a Finder window from today back to 8/18/19 . . Even though the earlier dates are visible on the slider control they are not available to view.

The screen shot of Time Machine from System Preferences confirms the "Oldest backup" as 12/29/17, and in the recent past I have been able to read back to the oldest.
I have successfully done a "Verify Backups" command for Time Machine.

I'm not sure how my backup got into this condition, but I'd really like to access some earlier backups from 2018 but I can't read earlier than 8/18/19.

Very much appreciate any suggestions on how to recover my backup and prevent this from happening again. Tnx

 

[HDFan]

Do you have any other backups? TM tends to get corruption problems.

 

[DonP]

Yes, I have other backups but none go back as far as TM did.

 

[HDFan]

Before you do anything I would get all of the data that you can from the drive. Messing with TM volumes can result in your not being able to access anything.

You can try running disk utility first aid on the disk. If that doesn't work you can then try some of the other disk recovery programs, such as DiskWarrior or TechToolPro. I've tried repairs in the past (there are some kn owledeable articles about fixing TM corruption on the web) but never got them to work. When I have a corruption problem now I don't bother trying to fix it, I just wipe the disk and start from scratch.

 

[DonP]

Thanks for the tips. I did DU first aid on the TM disk early on but no success.

What I have discovered is I can go to /Volumes/Time Machine Backups/Backups.backupdb/Donald's iMac/ and find a series of dated folders from 12/29/17 through today each containing the complete TM backup for that date. I found the .jpeg file I wanted from 2018 and copy/pasted it to my desktop.

So whatever corrupted my TM archive the actual data is still there and readily accessible with Finder.

I am starting a 2nd TM backup on an external SSD to maybe prevent this problem in the future.

 

[HDFan]

The data may well be there. TM uses pointer structures. When doing a new backup if the data is already there it just points to the data rather than backing it up again. The problem comes when these links become corrupted.

A couple of other points:

1. TM on an SSD is a waste of money. You don't normally don't need that speed for TM. It's similar that way to cloud "glacier" storage.

2. Make sure your other backups are not TM.

 

[BrianBaughn]

TM on an SSD is a waste of money. You don't normally don't need that speed for TM.

In this case, probably. It depends on how fast you want to be able to restore.

To the OP: Have you ever changed the name of your boot disk?

 

[HDFan]

It depends on how fast you want to be able to restore.

TM restores of small amounts of data won't be that much faster on a HD vs SSD. For large amounts of data, particularly a full restore, I would think a cloned HD restore will be faster than an TM SSD restore. TM restores are notoriously slow due to all of the links. Haven't tested though.

 

[Brian33]

To the OP: Have you ever changed the name of your boot disk?

I think this might be the explanation -- IIRC a very similar thing happened to me after changing the name of my boot disk. There was a way to get to the older backups, though. I believe that it was going into Time Machine interface and hitting Shift-Cmd-C (Finder's shortcut for Go to Computer) and then the old disk name showed up in the TM/Finder interface.

 

[ItWasNotMe]

Are you sure the folder that had focus when you were moving through the index actually goes back to the start of your history?

Example:
I have folder created 27th Dec 2019 - If I use Time Machine with that as the focus then that is the earliest date I can move the index back to

If I set the focus to be boot drive then I can go back through the entire history

 

[BrianBaughn]

I think this might be the explanation -- IIRC a very similar thing happened to me after changing the name of my boot disk. There was a way to get to the older backups, though. I believe that it was going into Time Machine interface and hitting Shift-Cmd-C (Finder's shortcut for Go to Computer) and then the old disk name showed up in the TM/Finder interface.

It's such an easy thing to do and the user isn't warned about the consequences.