Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you.

If I ask Time Machine to create a new backup for me, will it only do so on the Apple Time Machine module, leaving my other snapshots intact, or will this cause all snapshots on all disks to be lost? Hope someone can definitively answer this. Thanks in advance.

Other backups are left intact.. you can start a new backup to a different disk at any time.. that is effectively all you are doing.. and TM will continue to work with all the previous snaphots on the other disks.

Someone recently posted a fix for their corrupted backup. How general a solution this is I don't know.

Fix corrupt TM backup.

https://discussions.apple.com/thread/7258280?answerId=29263757022#29263757022

1) Disable Time Machine.

2) Stopping all Spotlight indexes (mdutil -d -a).

3) Destroying all Spotlight indexes (rm -rf /.Spotlight-V100) manually.

4) Repairing a file system permission issue with Spotlight (removed a bunch of folders owned by a non-existant user in a /private/var/folders subfolder that Spotlight created). No idea how they got there but they were there and the logs were complaining about them causing a fatal error.

5) Re-enabling Spotlight indexes and letting them build fully.

6) Re-running an initial Time Machine backup.

If you can't login to https://bugreport.apple.com consider registering as a developer in https://developer.apple.com – it's free if you're not looking to publish apps to the App Store.

Otherwise maybe take it to the media as a last resort? Long ago I've written an article that explains the underlying issue in a non-technical way as much as possible. Maybe someone could highlight this long-standing problem so that Apple's higher management take notice?

Thanks.

I just got the same error message and reported a bug report on bugreport.apple.com: 23548218

The result from "sudo tmdiagnose" was a 5 Mb zip file and was attached to the report.

My setup:

Mac Mini with MacOS X 10.10.5 with cabled ethernet network to a TimeCapsule. TC version 7.6.4

The TC WiFi is switched off, but it is connected to a separate WiFi router.

The backup of the Mini started in September 2010. Last successful backup 30. October 2015.

I also back up a MacBookPro to the same TC over wifi. No problems there so far.

I'll report back any response form Apple. And I will wait before trying the suggested fixes.

With the knowledge that I'd be able to keep earlier backups on other devices (thank you!), I just pushed the "fix it for me" button and let it run a day and a half or so. All seems okay now. But, what a pain!

danfrommountida wrote:

With the knowledge that I'd be able to keep earlier backups on other devices (thank you!), I just pushed the "fix it for me" button and let it run a day and a half or so. All seems okay now. But, what a pain!

TM has become too unreliable..

I strongly advise people now to buy an alternative backup.. eg Carbon Copy Cloner or Chronosync. I use the former.. it is faster and more reliable than TM.. without doing all the incremental storing of file versions to be sure.

I concur. After many wasted hours of research I've concluded the Time Machine is nothing more than a novelty. It may be different for other folks, but in my situation I have a Time Capsule, an Ethernet-connected NAS and a hard-wired USB drive. The USB drive is the only one of the three that it has never found reason to force me to discard all my legacy backup files with the phantom "unreliable backup" message. That drive is only periodically connected and stored offsite as a catastrophe mitigation measure so it misses many intermediate versions of files. I believe that Time Machine might work if you have two storage devices permanently installed inside your machine and connected 100% 24/7 to the main bus, but if you do anything novel like external storage, NAS or USB - well you are operating way outside the bounds of normal and are engaging in risky behavior with your data. I'm going to buy a commercial backup software package today and be done with this vexation.

Well, this is no good. I just got the same error. My TimeMachine is only a few months old. I just told it to create a new backup. I use CrashPlan as well, and all of my documents are on OneDrive, so not really worried. TM is my way to fully restore my entire machine in the event of disaster.

Will creating the new backup totally remove all of older stuff in the "corrupt backup" freeing space on the drive?

I did the same: 24600131

Bug report was submitted successfully.

Just checked the response from Apple on my report:

"Duplicate of 15971899 (Closed)"

I guess they need a few more cases before the issue is escalated.

The TM software and hardware (TimeCapsule) should handle power outages and network communications problems. That is more or less why we have them. I live in Oslo where we almost never experience power outages, but I noticed one suddenly one morning this autumn. If that was enough to ruin 5 years of backups, it is not good enough. Imagine having an unstable power supply as many (most?) people have. If a UPS is needed for reliable backups, Apple should either build a small on into TC to let it shut down gracefully or at least state the requirement clearly.

My Bug ID 24600131 is still open. They asked me for more information and to be able to replicate the issue. I have done this and resubmitted. Stay tuned.

rsterrill wrote:

I concur. After many wasted hours of research I've concluded the Time Machine is nothing more than a novelty. It may be different for other folks, but in my situation I have a Time Capsule, an Ethernet-connected NAS and a hard-wired USB drive. The USB drive is the only one of the three that it has never found reason to force me to discard all my legacy backup files with the phantom "unreliable backup" message. That drive is only periodically connected and stored offsite as a catastrophe mitigation measure so it misses many intermediate versions of files. I believe that Time Machine might work if you have two storage devices permanently installed inside your machine and connected 100% 24/7 to the main bus, but if you do anything novel like external storage, NAS or USB - well you are operating way outside the bounds of normal and are engaging in risky behavior with your data. I'm going to buy a commercial backup software package today and be done with this vexation.

Try using it in a supported manner. NAS is not a compatible destination and thus doesn't work correctly.

It's 2016 and this problem still exists with no explanation.

This makes time machine backup unreliable and thus, worthless.

this is not a problem for Apple, we have already bought our TMs and they are likely out of warranty

It nukes your whole filesystem.

It doesn't nuke your whole filesystem. It nukes your entire backup. Huge difference.

If you are a developer or have access to bugreport.apple.com file a bug report. That's the only way something is going to be done. Apple doesn't monitor these forums for bugs.