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

After reading this thread and several others on this site and other sites, it seems that most of the people having issues with the TM appear to be having the issue are with an iMac, which is also true in my case my MBP backs up with no issues but my iMac is a different story

YatBob wrote:

After reading this thread and several others on this site and other sites, it seems that most of the people having issues with the TM appear to be having the issue are with an iMac, which is also true in my case my MBP backs up with no issues but my iMac is a different story

I've noticed this too. My four-year-old MacBook Pro does this with no issues, but my one-year-old iMac has the problem regularly. In my case, the MacBook Pro is usually used in a part of the house where wifi is stronger (nearer to the Time Capsule) than the iMac's more distant (but still quite good wifi strength), location. Don't know if this is a factor.

I've been having this problem for quite a while also. It came to the point that it was happening almost monthly. I've tried every troubleshooting method I can think of.

I tried calling apple in December, after it happened for the fourth time in 2 months, but could not convince them this was a defective TC. They felt I had a corrupted file somewhere on my iMac, and wanted me to try some more troubleshooting methods, including zero formatting the TC, which I did. This seemed to help, but this week it happened again.

I've finally gotten to the point that I can't trust the TC for backups anymore, and bought a new external drive directly connected to my iMac (one nice thing is that it is usb 3.0 so doesn't take 18 hours to do a full backup). I'll see if this fixes my problem.

I see other people suggesting this is an issue with Sierra and Time Machine. I'm hoping that's not the case, which would mean my new HD was a waste of money. We'll see.

I'm really disappointed in TC, and that Apple doesn't seem to be addressing the issue, because I LOVED the idea of being able to do my backups wirelessly, and not have to manage any more cables than I have to.

It's difficult to imagine Apple being in complete ignorance of this issue if it affects all Sierra users or even a large segment of Sierra users backing up to a Time Capsule. This leads me to wonder if there isn't some other less apparent commonality between those of us who are experiencing it.

but that even after 6 months theres no acknowledgement or fix

More like 6 years, since this issue really started to appear when Lion (10.7.x) was introduced. Few users were affected by this back then, but a significant percentage of Sierra users have seen the problem based on the number of posts that have appeared on this forum.

Even regular publications have picked up on the problem, for example......

http://www.macworld.com/article/3170844/macs/when-backups-go-bad-the-problem-wit h-using-network-drives-with-time-machine…

Apple has always acknowledged the issue.....but no one knows when and if a "fix" will appear.

BobTimmons wrote:

. . . . Even regular publications have picked up on the problem, for example......

http://www.macworld.com/article/3170844/macs/when-backups-go-bad-the-problem-wit h-using-network-drives-with-time-machine

Very appropriate and enlightening article. The author says the Time Capsule has been discontinued, yet I note they are still for sale in the Apple Store part of their website. I have heard that is Apple's intent, though. Seems like we all need to come up with a reliable, long term, backup replacement strategy that keeps us comfortable without Time Capsules in our future.

My Time Machine/Time Capsule backups are up and working again on my iMac and MacBook Pro, after the corrective action I reported above, but who knows when they will have to be replaced with a new backup again?

Because of dicey Time Machine/Time Capsule performance, for some time I've been using Super Duper to perform manual backups to a hard drive USB-connected to my iMac. Many of us also have our stuff in the Cloud these days, so I'm thinking that may be adequate for someone like me.

It really is too bad, this Time Machine/Time Capsule performance is going down the drain. One of my greatest successes with it was when I had to wipe our MacBook Pro clean during performance troubleshooting a couple of years ago, and was able to very easily restore it from the Time Machine backup.

Because of dicey Time Machine/Time Capsule performance, for some time I've been using Super Duper to perform manual backups to a hard drive USB-connected to my iMac.

You may already be doing this, but you can also use Time Machine to back up to a USB drive connected to your Mac. Time Machine backups should be a lot more reliable this way, compared to backups to a network drive like a Time Capsule.

In the last few years, I've had an iMac backing up using Time Machine to both a Time Capsule and a USB drive connected directly to the Mac. Zero issues with the USB backups, and an average of two or three corrupted backups per year with the Time Capsule.

Not sure if SuperDuper has this capability, but Carbon Copy Cloner will allow you to back up a Mac to the Time Capsule drive as well. I've had zero issues with this, compared to a number of issues with Time Machine.

I don't doubt that some had problems with Time Capsule backups prior to Sierra, but I for one never did (except when our original Time Capsule itself failed). We have two same-generation iMacs backing up to the same last-gen Time Capsule. The one running Yosemite has never failed. The one running Sierra, as often as weekly. The iMac running Yosemite is going to stay that way.

As an 8 year participant on the support forums, I can say that we've seen this issue for almost 7 years. The problem first appeared in May 2010. Personally, I worked with Apple Support at that time as part of a support project to furnish them with regular updates on the issue.

This support article, which was originally written over 6 years ago will tell you more about the issue. It also confirms that the issue first appeared in Snow Leopard (10.6.4), spring 2010.

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

As I've mentioned previously, my opinion is that a larger percentage of Sierra users have been affected by this problem than any other previous operating system.

If Apple has not fixed the issue after 6+ years, I doubt that it has ever been high on their priority list.

Well, I've had a Time Capsule since they were first available. The ease of backup and recovery was amazing utilizing a Time Capsule and Time Machine. I have not had any problems other than disks eventually giving out. I bought new one last March with the faster WiFi, no problems until macOS Sierra. It is absolutely technically incomprehensible to sell a backup system that is no longer reliable with your existing operating system, or to be so slow to remedy such an important personal and/or business data protection mechanism. This has me absolutely livid, having a backup system that is absolutely unreliable and has been broken at least since macOS Sierra! I am ready for a class action suit!

I've been here for 12 years though obviously more as a lurker than yourself. I don't think we're disagreeing really. What we don't know beyond anecdotally is how much (and I don't suppose it's a question of whether) the issue has gotten worse with Sierra.

Pond has always been my go-to on other issues I've had with Time Machine but his support pages haven't been updated in years (did I not hear somewhere that he had passed away?). He did manage to uncover more quirks in TM machine than anyone else.

Since I assume that not everyone is afflicted by this problem (Apple would be forced to deal with it, if that was the case), I suppose I am continuing to hope against hope that some commonality on who is getting it and why could be discovered. I have no idea where to start with this, though. Any thoughts?

The issue has been with us for almost 7 years. Apple acknowledges that it exists, but has not acted any further. If you call Apple Support, you may or may not get a reply of something like "we are working on it".

If that is true, then Apple has been "working on it" for almost 7 years, since they were "working on it" when I first contacted them long ago. Whether or not they really are "working on it", I don't think we will ever see a solution, but that's my opinion.

If you decide to call Apple Support and receive some significant "news", please post back to let us know.

James Pond and I communicated with each other on almost a daily basis for several years. I don't have the exact date of his passing, but it was not long after the Lion operating system was introduced. No one in the world knew more about Time Machine than "Pondini".

After digesting the many good comments here, I conclude that one major variable in performance could be the strength of the wifi signal at the computer, and the potential for interference in it during backups.

My anecdote, as stated above, is that I have an iMac and a MacBook Pro both running Sierra. My MacBook Pro never has the problem discussed here, and is located near the Time Capsule where there is a very strong wifi signal with no potential for interference. My iMac, which does have this problem, is used in a location more remote from the Time Capsule. While the wifi signal at the iMac is rated as "excellent," it is somewhat weaker and located nearer to a neighbor next door which iStumbler shows as a high potential for interference. Yes, I have set my wifi system to a channel with the least likelihood of interference, but I believe it still can happen. So, I conclude this problem may occur for me because of wifi interference.

If my case is typical, it seems that is beyond anything Apple can control, except that it does seem like it has occurred more since Sierra. FYI.

I wish I could confirm your theory. Our two iMacs are located less than ten feet away from the Time Capsule. As has been pointed out elsewhere, the issue can occur on network drives whether they are connected via wifi or ethernet. Though again we are lacking data on the frequency of the problem in various configurations.

FWIW, I am having some success using Time Machine Scheduler reducing the backup intervals to couple time per day. I know it will probably fail again but with luck not nearly so quickly.

As for Apple Support, I am probably not eligible for free calls at this point, since our last Apple purchase was over a year ago now and I don't buy AppleCare.