OS 10.15.5 + Time Machine incompatibility

This message is Apple's polite way of saying that your Time Machine backups are corrupted and unusable. This does occur a lot more often on Macs running the Catalina 10.15.x operating system. Apple has not provided a "fix" for this.

You will need to click Start New Backup to have Time Machine erase the existing backup for the Mac that you are using and start over again with a complete new backup of the Mac. This will take a long time.

You will then need to do the same thing with each Mac that displays the message below.

If you are saying that you are clicking Start New Backup and nothing happens or the same message appears, then there are other issues.......like a failing hard drive on the Time Capsule.......that will need to be addressed.

The release notes from Apple for 10.15.5 make no mention of any changes to Time Machine and a check with Apple Support today confirms this, so we don't really have anything firm to work with here. We've seen users report problems at an increased rate ever since 10.15.5 was released a year ago.

The real issue though for the moment is the messages that you are receiving. What's done is done. Your backups are corrupted if you are seeing the dreaded message below:

You have two options at this point:

1) Click Start New Backup to erase your old backups and start a new backup again from scratch

2) Click Back Up Later and no new backups will occur until you click Start New Backup

I have the same situation occuring. My OS is Catalina 10.15.5 ... and for the last few weeks my backups have all failed the same way. And every attempt to start a new backup results in the verification error dialog as described. I have backed up to an Airport that I have used for years with this result. And I have tried going to a Western Digital NAS drive - with the exact same result. I have tried non-encrypted and encrypted to the Airport. So far I have only tried the unencrypted on the WD NAS box but I just started an encrypted backup - but won't know the reuslt for a few hours. I am beginning to believe this is an OS or Time Machine software bug. I have tried using the Airport over wireless and over a wired connection - again, same result every time.

Does anyone else have this issue or suggestions ... ? Oh, and I am in the process of erasing the Airport via the multipass erase mode - just in case there is something wrong with the drive.

Well, you could try the 10.15.6 update that Apple has just released. Did not work for me, but you never know.

My opinion......Time Machine is broken backing up to a network drive. Don't use it with a Time Capsule or a NAS. Seems to work fine if you connect a USB drive direct to the Mac and back up that way.

Erasing the Time Capsule drive might help......the question is for how long. I never got more than a few weeks use before the dreaded messages started to appear again.

Meanwhile, Carbon Copy Cloner backups to a Time Capsule have worked flawlessly for years.

Thanks - I will (over the weekend) pursue your advice. I have the .6 upgrade on my other Mac. But it has a separate local drive andhas not had the verification issue (ever). Also, I think it will take until tomorrow some time to completely erase my Airport so I'll try it again after that is done. I will probably upgrade to .6 before even trying anything else, though.

Good luck. No mention of anything related to Time Machine that I can find in the release notes for 10.15.6.

Things will change significantly with the next operating system, but we'll have to wait and see.

Again thanks - and I agree about the next major upgrade. Who know what might happen there ...

Oh, I might actually go get Carbon Copy. I have thought about that for years but never pulled the trigger.

Thanks for the help, though!

My iMac with Catalina 10.15.5 is in the same loop with Time Machine backing up to AirPort Time Capsule. The first time I let it start a new backup, it wiped out all my old time machine history, finished a new backup which I can see and from which I can restore selected test files. Rinse and repeat. I have checked to be sure I have the latest AirPort firmware, and restarted the base station, to no avail. I continue to get the verification error dialog daily but have learned to tell it No.

Interestingly, my husband's iMac Pro, also Catalina 10.15.5, continues to back up successfully to the same AirPort Time Capsule!

Has anyone tried contacting Apple Support with this issue? I don't know what else to do.

Ok - so today and yesrterday I experimented with backing up to two separate networked drives. One is an Airport (from Apple) the other a Western Digital drive. Both backed up successfully the first time(s) - I did both encryped and unencrypted backups. When the backups completed - a short time later backup tried to run again. And every time - the verification error message (as reported in this thread) appeared. There was no way to continue without re-starting the back up process ... which also fails!

Today I also purchased a local USB drive and performed a backup! This backup is passing the verification test!

I also tried to call in to Apple Support. Unfortunately - I am unable to get to talk to anyone or even to chat with anyone. I have given up completely on pursuing their help. The only problem I seem to be having, right now, is that Time Machine completes a backup and restarts shortly after it is done. Much faster than I really wanted ... but that is fine.

Hope this helps others on this post.

Maybe this will help someone.... After 2 calls with Apple Support ..... and a Reinstall of Catalina.....

I almost reformatted my entire HardDrive..... I had a hunch and Uninstalled my Norton Anti-Virus. I restarted my Mac and did a full back-up and that fixed the problem.

Time Machine is working perfectly now.

Rain

Maybe this will help someone.... After 2 calls with Apple Support ..... and a Reinstall of Catalina.....

I almost reformatted my entire HardDrive..... I had a hunch and Uninstalled my Norton Anti-Virus. I restarted my Mac and did a full back-up and that fixed the problem.

Time Machine is working perfectly now.

Maybe this will help someone.... After 2 calls with Apple Support ..... and a Reinstall of Catalina.....

I almost reformatted my entire HardDrive..... I had a hunch and Uninstalled my Norton Anti-Virus. I restarted my Mac and did a full back-up and that fixed the problem.

Time Machine is working perfectly now.

So ... I will admit that I am not excited about the cause, but actually not all that surprised.

I found that the issue only occurs on networked drives, as I have two MacBook Pros and only the networked drives had the verification error. And once I got a local drive for the second Mac, it worked, too.

And now ... it sounds like I could remove Norton and then go back to networked backups. But I do like having norton running and I have local drives now so I don’t have a pressing need to go to the network route.

I am curious ... did Apple support say they would report the issue to Symantec? By chance ...

Oh ... thanks for posting! You really helped me understand the situation!