Time machine preferences shows disk unavailable but still backs up, just missing 2 months of backups

Last (I hope) update on this issue. The new backup is operating correctly. The first backup was completed on 3/3 and is correctly reflected both by looking at TM preferences and Entering TM. Daily backups for 3/3-4 and multiple backups for 3/5-6 are visible and accessible.

While no answer to the question of the growing backup gap between 8/8/20 to 12/22/21 and the current "today and yesterday" was ever determined, creating a new backup resolved the problem. As I mentioned earlier, I will delete the old backup sparsebundle after confirming there is nothing I need from the prior two years, of which I'm very confident since my wife never deletes anything from her Mac so probably has everything on her machine that's on the backup. 😉

Deleting and creating a new backup seems to be the only resolution when TM appears to get "lost". That is also what I had to do in Aug 2020 when I had issues with Disk Not Found errors and/or only the most recent backups being available intermittently. That backup ran fine until this issue started. We'll see whether I get another 2.5 years out of this one.

Thanks to all who contributed suggestions on this thread!

Regards,

Howard

Thanks for the prompt response! None of the TM issues in the Monterey discussions I could find seemed relevant - please forward a link if you have seen one you believe fits.

Since I use the Time Capsule for multiple machines, my preference would be to not reformat the disk. I could delete the Mac backup and create a new one, but once again, this should not be necessary since both the Mac and PC are accessing the disk and backups are running successfully, but Time Machine is simply not recognizing the additional backups. I don't know how I can see two days of backups at the same time that it claims the disk is unavailable.

I'm currently running Disk Utility's First Aid to see if there are any issues that could be contributing to this issue and will post the results.

Disk Utility First Aid found no problems, no change in the disk availability icon in TM preferences, but backups still ran successfully. Then ran disk verify per Bob's suggestion above, and there is no longer the red i icon in TM preferences and backups still run successfully, so I'll see whether I get more than the yesterday and today backups over the next few days.

Thanks @Bob Timmons for the Disk Verify suggestion!

Bob -

Interesting info on Disk Utility.

The info displayed on the DU home screen includes both the full 1.9TB Apple Disk Image Media and the Used/Free disk image volume subfolder for the Mac Time Machine Backups underneath the full media, in addition to the Apple SSD and Mac HD images. You would think that if the TC was not supported in DU it wouldn't appear, or report that it ran successfully.

DU claims to have run successfully and has what appears to be a complete and correct set of info on the drive, but I do see that while the Apple SSD Media has the Container disk 3 subfolder that includes the red Data bar on its display, the Macintosh HD subfolder just displays the blue used storage bar, which is what I see on the TM. Is this your reference to not seeing "data" on DU?

Running disk verify as you suggested has eliminated the red i icon in TM Preferences (Thanks!), and entering TM shows 9 successful backups yesterday and 11 today, but the next most recent backup image before yesterday and the Latest Backup date in TM preferences still shows 12/22. I'll check again tomorrow to see if I see three days instead of just two, but the Latest Backup date in TM preferences is not encouraging.

If the backups continue to run successfully but I can only see the current and previous days, I still may need to archive the current backup and create a new one, but if you have any other suggestions on how I can retain my current backup and get everything working properly, I would certainly appreciate it.

Thanks and regards,

Howard

LaPastenague -

Thanks for the additional suggestions! The Mac is of course out of warranty, so Apple Support isn't an option. Clearly the disk is not lost since backups are always successful and after running disk verify per Bob's suggestion, the red i icon is no longer an issue in TM Preferences, the disk doesn't need to be rediscovered.

As I said in my response to Bob, barring any additional suggestions that work, if i continue to only be able to access my 2021 and earlier backups and the current and previous day, I will likely need to archive this backup and create a new one.

Regards,

Howard

Bob -

Thanks again for your prompt response and insights! See my responses inline below preceded by h>>.

Regards,

Howard

You would think that if the TC was not supported in DU it wouldn't appear, or report that it ran successfully.

Disk Utility can display the special sparsebundle image file on the Time Capsule disk, but it cannot display or check the actual Time Capsule hard drive.......named "Data" by default. Even if you have changed the name of the Time Capsule hard drive, it will not be displayed in Disk Utility. So, in the event of a possible physical problem with the hard drive on the Time Capsule, Disk Utility will be of no help.

h>> Makes sense, though the DU UI could be more explicit about its capabilities. There doesn't seem to be any physical defect on the drive, since backups from both the MacBook and my PC work fine.

Running disk verify as you suggested has eliminated the red i icon in TM Preferences (Thanks!), and entering TM shows 9 successful backups yesterday and 11 today, but the next most recent backup image before yesterday and the Latest Backup date in TM preferences still shows 12/22.

Are you saying that there are two or more sparsebundle images for the Mac on the Time Capsule? If that is the case, then Time Machine started all over again with a new backup. To possibly see the "old" backups using Time Machine, try the following:

Hold down the option key on your Mac while you click on the Time Machine "clock" icon at the top of the screen

Select Browse Other Backup Disks to see if the old backups might be there.

h>> Only one sparsebundle and one Windows backup are on the TimeCapsule. TM is accessing the single sparsebundle, as indicated by TM preferences having the correct oldest backup date of 8/8/20 and free space, and my being able to access all of those backups, as well as the backups from the "rolling" today and yesterday. The only anomaly is the continually increasing gap of missing backups from 12/22/21 to "the day before yesterday".

Finally, not sure if you were aware of the additional challenges in Time Machine with Mac's running Big Sur or Monterey. If you are using one of these operating systems, your Mac's hard drive was changed to use a new format called APFS. But, the Time Capsule hard drive can only be formatted in HFS+.

So, Time Machine tries to back up APFS formatted data to the APFS sparsebundle image file on the Time Capsule, whose hard drive can only be formatted in HFS+. Gosh, I wonder what could go wrong with this extra complexity.

h>> Never a dull moment with "improved" file formats and software versions! ;-) We replaced our 2013 x86 MBP with this M1 Mac Air in Nov 2020, which I believe included Big Sur, and if it didn't I would have updated it as soon as it was stable. TC has been working fine for both the old and new Macs and the PC as I updated the OSs over the years, and worked for both read and writing backups through 12/22/21. It's just this growing gap in accessing backups over two days old since 12/22 that has been puzzling me.

Personally, Time Machine backing up to a Time Capsule has not been all that reliable for me since Big Sur was introduced. I keep a Time Capsule around to help answer questions on this support forum, but I do not trust it as my primary backup plan.

h>> While I'm sure I will need to replace it eventually, the TC has actually been pretty reliable for me. I did replace the disk a few years ago, but other than that it's actually been pretty good. I have it connected via Gbe to my router with the TC wifi disabled, so using it only as a network drive. TC is our local backup, but we also back up all our devices to the cloud.

My problems always tend to be more interesting than the typical problems users have since I can manage most issues on my own... ;-)

If the issue isn't resolved this week, I'll have the TM start over with a new backup and retain the old one for a month or so to ensure I don't need anything on it which is unlikely. The Macbook is my wife's and she rarely deletes anything, so she probably still has everything on it that's on the two year old TC backup.

Thanks again for all of your insights!

Regards,

Howard

A quick update.

Once again, there was no change in the Last Update date in TM preferences with the existing backup, and I could only access the backups for yesterday and today followed by the 8/2020-12/2021 backups. I moved the existing sparsebundle to a new directory and am currently creating a new backup. Assuming that this new backup runs successfully over the next week and I have the ability to access data for all dates, I will delete the old sparsebundle and consider this closed.