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

My best use case for Time Machine is when migrating to a new laptop. It doesn't seem to work as well for locating single files that have been corrupted, or mistakenly deleted. I have added an online backup service for my photos and documents, and that makes me feel much more secure. I guess that's good backup strategy anyway -- multiple copies in multiple places on multiple media.

Hi, No need to go into great detail but suffice to say I tried sorting it myself, called Apple Support twice over a 10 month period, all with no success in resolving the issue.

Finally I just turned off 'Automatic Backups' & resorted to manual backups, my choice as to how often I do said backup, which really is no big deal in the scheme of things.

Guess what, for me personally no further problems at all, 8 months or so now & not one dreaded message that a new backup needs to be created.

It will be interesting to see if this works for others or whether I was just lucky (in some ways) but unlucky in respect of Apple not, publicly, recognising & sorting out this issue a long time ago, shame on you Apple!

This is more than 5 years later than the original question. I just got that same message yesterday.

I am running Sierra10.12.6 now with a new MacBook Pro 15" with the USBC ports.

I had been running Yosemite with my older 2010 MacBook Pro 17". The time capsule had backups since Snow Leopard. And I did use it to restore files several times.

I never got that message before but did have other problems with my backup so I erased the time capsule and started from scratch when I got the new MBP 15 in January. The backup file had been working ok until yesterday. I looked at the backup file and there was nothing in it at all. So I did let time capsule create a brand new backup. It took 14 hours directly connected to the time capsule with a cable. But I am not sure I should really trust this new backup.

I am backing up to a Time Capsule, and have just started to get the same error-

iMac 2017, Mac OS 10.12.6, latest Time Capsule 3GB

Just got a new RAM module installed because the last one failed- since I got it back, it has thrown up this message overtime I try to back up.

Weirdly, I can enter access my Time Machine backups through the timeline - but it just won't back up anymore.

I also use the same Time Capsule to back up my MacBook Pro- and have had no issues with that machine.

AppleCare was unable to help, and advised me to delete my existing backup, and start a new one- but my Time Capsule holds valuable past versions of academic papers, so I would take hours to pull them out first.....

Anyone had any luck with a fix yet??

Hi, No offence meant coocooforcocopuffs but I do not back up multiple machines & never have, my "Message" about needing to create new back up just starting happening.

I do agree though that, thats the way it is, sadly. I'm guessing Apple don't really know what to do about it otherwise we would hear from them publicly

I've had at least five of these kinds of TM errors on my Synology 1515 NAS since I bought the thing in June. Both in El Cap and now Sierra, although it seems to be worse now. I'm new to NAS and bought the thing because I have about 10 TB scattered around different drives and I wanted them in a unified TM backup because it's a pain otherwise. Trying to triage it with exceptions to fit on hocketed 8TB TM drives has been expensive and inefficient, as I still had to do manual backups of some of it. I really need drives of 12-14TB to do single-drive TM properly and they don't exist.

Also, I had a lot of problems with 8TB drives going bad. Synology's SHR2 striping allows 2 drives to fail, so I figured this was a good solution for TM. 5 bays x 8TB with all the striping still gave me a lot of breathing room at 23 TB. I figured that was safe. I figured I'd get a couple of years of TM backups without worry.

I thought wrong. As good as Synology NAS devices are, they can't protect one from corruptions caused by un robust software from apple.

The first couple of times when the errors occurred, I was successfully able to use Disk Warrior and/or the lengthy terminal process outlined in the article earlier in this thread to repair the .sparsebundle drive image. But the last two times, this has not worked. I have used the NAS both over wired Ethernet and over wifi. It doesn't seem to matter, as the errors occur either way. So then it's off to reformat the NAS and do a shiny new backup which takes tens of hours, yet again, and again my incremental backup history is hosed. I have no backup history since June.

I do also use Backblaze, but it has its limitations, I was hoping to have another way to access TM files remotely, I have now spent dozens of white-knuckled hours on this vexing issue and I've had it.

Until and unless Apple fixes this NAS/TM corruption, the only solution I'm coming up with is to abandon NAS and buy a wired Drobo or other wired enclosure with RAID 6. And that's probably my solution.

As the history of Time Machine and NAS's is rather checkered (they have gone from unsupported to poorly supported) I see no reason at all to recommend or even suggest one, failure is the common end result and I will continue to tell the people who come here to tell us that their NAS does not work why it does not work reliably.

Bob Timmons wrote:

You told us that NAS drives are not supported. This is not correct. I have used one for the last few years.

You are entitled to your own opinion about network drives, but not to your own facts.

The support is very poor, as witnessed by the fact that this forum is littered with posts from people whose backup to a NAS is unreliable. An unreliable backup is no backup at all.

I have had no issues with Synology NAS. Run backups now for over a year. They are certainly not cheap.. so buying a NAS would have to have more justification than simple TM backups. But it is much much faster that TC and is great as file server, as well as media functionality built in.. remote access.. vpn etc etc.

Since Sierra the problem of TIme Machine reliability to any network target is so great that I also recommend using Carbon Copy Cloner.. as well or instead of TM.

FWIW after my fiasco with the Synology NAS, I've had a Drobo 5c connected over USB for about three weeks and am using the same drives in it. Using it exclusively for TM. No problems so far with corruption, though if/when budget permits, I'll probably get a second one as a backup and rotate them. I do recommend that anyone using a RAID solution for TM run Disk Warrior on it at least monthly, whether NAS or not.

10 days to go before the end of 2017, and this problem appears to have been resolved (for me, anyway) by disabling PowerNap.

I know it seems too good to be true, but I would never assume that Apple would have fixed it by now if that was the source of the problem. Who knows how long their bug list is and how it is prioritized. If I recall correctly, though, it was an Apple employee in one of these threads that suggested it could be PowerNap related.

I have several other Macs on the same network, using the same drive for backups, that have never had the problem. But since I tried the disabling PowerNap on the Mac that was having the problem (repeatedly!) it has never recurred.

No new drive. No more reformatting. All I can say is disabling PowerNap (only on the Macbook having the problem) appears to have solved it.

I agree with Bryrock. After almost six months having turned off PowerNap on my MacBook Pro late 2013, I also have not seen this problem again (knocking wood). I did the same thing on my wife's iMac, which had the problem twice in the past 18 months, and no recurrence there either. Seems like this is the likely culprit and highly recommend those with this problem to turn off PowerNap.

I'm using Time Capsule with an external USB drive hung off it. The internal drive is for my wife's laptop and mine is supposed to back up to the external drive, but it's been months since Time Machine was functioning.

Based on the above post, I tried disabling PowerNap. In an apparent effort to be really unscientific, I also did a hardwire connection to the backup drive to speed up the initial backup, which after weeks was still "waiting to complete" over wifi. Then after that was done (took overnight) I hooked the backup drive back to the time capsule and set up TM to back up to that drive.

I'm not sure if the PowerNap disable or the hardwire initial backup solved it (or perhaps the 10.13.2 MacOS update?), but after 4 or 5 months Time Machine is finally working again over WiFi!

This is a perplexing message when it appears.

Your backups are corrupted, and Disk Utility cannot repair them. This message rarely appeared until users started installing the Lion operating system.

We do not know why this error sometimes occurs.

You may be able to get into Time Machine if you need to restore a file or data, but as soon as you click to start a new backup, Time Machine will automatically erase the Time Capsule and start a new backup.

You might want to contact Apple Support directly for more information. They have been very silent about this.

http://www.apple.com/support/contact/