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

I just got the same message on my iMac running El Capitan. I back up to a QNAP NAS and have had no problems up until now. In fact I even had to restore form a back up recently as my hard drive failed and had to be replaced. I would love to know what has prompted this message and what it really means. Since my hard drive failure I have begun backing up offset as well as via TM. I use Backblaze which was suggested to me by someone at an Apple store. The initial backup took close to 10 days but couldn't back up my NAS since that is also where TM runs and for some reason a volume that has TM backing up to it cannot be backed up by Backblaze. I do store my music on the NAS which fortunately is a RAID-1 set up so I have a mirror of everything so it isn't as critical. My photo library is on a separate external drive that Backblaze does back up.

I would love to know what has prompted this message and what it really means.

This message appears when Time Machine has determined that your backups are corrupted and Disk Utility on your Mac cannot repair them.

it means that Time Machine will delete your existing backup file and start a new complete back up of your Mac and move forward.

This issue has been appearing since Apple introduced Time Machine, but the occurrences seem to be increasing rapidly. For example, we see 8-10 posts on average, per day from users who are seeing this message. A few years ago, we saw a few per week.

Apple has always been....and continues to remain.....very silent as far as a solution.

More info.....which is somewhat dated......is here, if you are interested:

http://pondini.org/TM/C13.html

Allez, go back to page 2 of this thread where I posted with the same problem following a Hard Disc Drive replacement. The new HDD UUID is different to the old one and so Time Machine does not associate it with the backups that it has been making previously. There are a couple of Terminal commands that can be used to try and get Time Machine to 're-associate' the sparsebundle. Although I did not discover this before I allowed the new backup to be created, it would appear from threads that I found in searches that others were able to reassociate their backups to recover their history using these commands. Other more expert aficionados here may enlighten you more. Good luck. Speckled James

Ive now had this twice in the last two weeks - for an Apple Time Capsule.

First time I had accepted the create new backup option, but as its happened again Im starting to suspect the disk in the time capsule...

If there is a firmware/software error that is affecting the disk, then erasing the Time Capsule using the Zero Out Data option in AirPort Utility may help. This is a "complete" erase, not a "Quick Erase", so it may take 4-6 hours depending on the size of the disk in the Time Capsule.

If you still have issues after a Zero Out Data erase, then there is likely a physical defect on the Time Capsule disk, and that means replacing the hard drive in the Time Capsule.....if it is less than 3-4 years old.....or replacing the Time Capsule if it is 3-4 years or older.

Erase your backups from Time Machine, use zero out data as that will find any issues. You may find if you have an iPhone/iPad that then looking at the drive from there it will tell you the problem more easily than airport utility on the Mac.

If there is a problem with the hard disc then unless it is under guarantee get a new one. I'm told that the machines are so fiddly to fix that if under guarantee you are likely to get a straight swap

I was seeing this error weekly, but I have not seen it in well over a week since I changed the Time Capsule IP address back to fixed (I had configured it as fixed earlier but it somehow switched itself to DHCP).

HI,

I'm having this error message problem as well . Is there an idiots guide to changing the Time Capsule's IP address to fixed? The Time capsule is the router for all my devices so not sure if I need to fix the IP address of the internal disk or the TC itself.

Many thanks,

Adam

I have set mine to Static twice, and it has switched itself from Static back to DHCP both times. I discovered the second switch-back yesterday, when the backup failed again due to this error. So I don't know the answer to your question but if the Static address setting won't stick then it won't solve the problem.

I went for a number of weeks this time before seeing the failure again. I am going to try setting an address reservation in the router. How you do that or whether you even can do it depends on your router.

Same problem here. I have created a new backup every time and it happens approximately every 7-9 days. I am using Apple's very own 3 tb Time Capsule. Nothing you can do but hope Apple will fix it soon. I am running Mac OS Sierra. I have three machines backing up to it and only one produces this error.

So I got the same message 3 times in three weeks - and i assumed that i had a disk issue. After adding an external seagate 5TB drive (they are pretty cheap now) to the Time Capsule I did the first backup - and 2 days later the "Time machine must create a new backup for you..." has popped up !!

So now I think it must be the capsule itself - I'll see if after another first backup (and turning disk sharing off) whether it re-occurs.

Let us know. My TC's hard drive failed so I started backing up to an external drive plugged in to the TC (wifi side works just fine) but now I'm getting the same error message, despite the backup being on a different drive now.

It must either be the TC or something within Sierra.

David, I too have had problems but from advice on this discussion and from others, I have since been running my backup without further notifications or apparent errors. You can see my thread in earlier pages for 2 incidents one in 2012 and the second in 2014. I mistakenly allowed the creation of a new backup in the first instant, where new hard drive UUID was the issue. I did not allow new backup on the second occasion but I removed non-apple software and that seemed to allow Time Machine to backup correctly to the Time Capsule which I originally bought in 2010. I got this message again around September this year (2016) and again this time I persisted to make it work. After a discussion and I now cannot find which discussion site I had this and with whom, but one of the more expert Apple aficionados told me to get rid of any non-Apple software, any anti-virus, antimalware and software such as CCleaner, even though I had taken most if not all of these apps from the App store ages ago but they were no longer app store promoted. I was reliably informed that such software which is non-Apple is really not needed to keep the iMac sweet. After I cleared all of this type of software and apps from my iMac the Time Machine, which had been stuck on 'preparing backup' for ages, miraculously kicked back into action and created the next backup. Unfortunately I cannot tell you which of the Apps was the cause of the issue. I haven't replaced them, I obviously didn't need any of them, oh and the iMac runs quicker. At the same time as I was having problems, I attached an old PC, but Mac OS Extended (Journaled) formatted, 1 TB Hitachi hard drive through an IcyDock USB connection direct to iMac and directed Time Machine to make a fresh backup on it. Once the original TC started to accept backups again Time Machine started to alternate backups hourly to both drives, so now I have my original TC backup set from 2014 and a spare set of backups started in Sep 2016. The more experienced Apple aficionados on here may enlighten you more about this. I now think that watching all the comments about both Time Capsule and NAS and other drives being used for backups, that other software is interfering with the Time Machine process and making it hang or report verification errors. Hope this gives all some thought and help. Those with computer science knowledge of OSX maybe could confirm or refute. The 2010 iMac and Time Capsule are nearly as sweet as the day I bought them in July 2010 although it is nearly time to treat myself to the latest variants. Good luck. Speckled James

Do you mean remove ALL third party software of all kinds? In other words remove Office, Acrobat Reader and so on? Or just things like anti virus etc? I have no anti-anything software or cleaner software. I did a disk erase on the TC which found an unrepairable disk, so now use an external plugged into the TC, which is now also bringing up the same error message, though I haven't wiped that disc and don't intend to, as it currently holds more than just a backup.

I think you're right that there is probably a software issue causing some problems as well (quite a few people seem to be reporting this issue) but I think mine is also mixed with a bad HDD inside the TC.

David, I am not sure about all third party software as I do not use any of those you mention. The likes of Office etc should have been Apple certified as they stock and sell them so you are probably OK with them. Acrobat is another matter, I don't think that it is stocked by Apple. I just use Preview for reading PDFs, and Apple software creates pdfs from other documents, however to edit pdfs something else is needed which you may find in the App store. I only need to use the Apple suite as it converts all its documents to Office style and pdfs to send to others. The Apple suite is perhaps not as powerful as Office, but I no longer need that complexity. What I have recounted in this discussion thread worked for me. My Time Capsule is now 6.5 years old and still working fine. Why not connect the external drive into the Mac to bypass the TC which may have the issue that is causing the verification failures? Perhaps book the TC into the Genius bar and let them have a look at it? If there is a fault they will find it and if it is within warranty replace it or even if it is outside warranty but at fault may still replace it. Any more is outside my ability as I do not have a Computer Science degree or OSX software depth of knowledge. I just love the fact that when I switch on what I have it just works and works first time. I have never had to reload any software update and I have updated everything since 2010, iMac, iPad, iPhone and Apple TV and they all synch with each other. This never happened before I moved to Apple. I won't bore you with my woes of maintaining the many PCs I have owned, and I built some of my own, never mind trying to get the conflicting software from dozens of providers to work properly and all the rest of the PC cleanup pfaff. Regards JR