Time machine backup not running

There’s another thread discussing this issue and an interesting point has come up. A user who seems to know what they are talking about says that this issue appears only in a specific case. If you upgraded from Yosemite using the original .0 installer and then applied the 10.11.1 delta update you experience the problem. If you did a clean install of El Capitan (either the original or the 10.11.1 installers) the problem doesn’t appear.

It would be interesting to learn how some of us updated to see if the pattern is valid. In my case I updated from Yosemite to El Capitan using the original installer and I do have the problem as predicted.

lkrupp wrote:

There’s another thread discussing this issue and an interesting point has come up.

FWIW, the link to that thread is Time Machine not doing hourly backups on El Capitan

It would be interesting to learn how some of us updated to see if the pattern is valid.

I did a regular update via the Mac App Store. I also have this issue with my 2012 iMac with an APC UPS connected to it. Disconnecting the USB cable from the iMac during startup & reconnecting it after logging in works for me.

Initially, I installed the El Capitan upgrade but didn't notice the Time Machine issue until a couple of days later. After doing a number of routine troubleshooting steps at the behest of Apple Tech Support, I erased my late 2013 Mac Pro and did a clean install of El Capitan. The Time Machine problem wasn't, in my case anyway, resolved with a clean install. However, just as you and others have reported, if I unplug the UPS, restart my Mac Pro then plug the UPS back in, Time Machine works as it should. It hasn't missed an hourly backup for weeks since implementing this workaround.

Ditto for me, @R C-R... I'm eagerly awaiting the official 10.11.2 release and experience tells me it may be a good idea to download and apply the combo update rather than the usual method too.

lkrupp wrote:

There’s another thread discussing this issue and an interesting point has come up. A user who seems to know what they are talking about says that this issue appears only in a specific case. If you upgraded from Yosemite using the original .0 installer and then applied the 10.11.1 delta update you experience the problem. If you did a clean install of El Capitan (either the original or the 10.11.1 installers) the problem doesn’t appear.

It would be interesting to learn how some of us updated to see if the pattern is valid. In my case I updated from Yosemite to El Capitan using the original installer and I do have the problem as predicted.

Back when those on this discussion thread first started troubleshooting this issue, there were a few people who made the effort to try running off of a clean install of OS X 10.11.0 but this didn't fix the issue.

I'm not sure if anyone effected made the effort of trying a clean install of OS X 10.11.1 as the individual in the other message thread indicates. I am willing to entertain the possibility that this might actually work, but at this point I'm just going to wait for the 10.11.2 update. If that doesn't fix the issue then I may night the bullet and make the effort of trying a clean install of that version.

Anyone installed today's update (10.11.2), and can confirm that this bug is fixed, please?

It appears that the update has fixed the problem. I did an additional restart with the UPS plugged in just to be sure. The backups are running. So far so good.

Thanks so much for letting us know, Glenn!

You're Welcome Mark

Just for additional info, I updated using the app store's incremental update from 10.11.1 to 10.11.2. I did not use the combo updater or the full installer from the app store.

FIxed on my Mac Mini 2012 with Cyberpower ups usb connected .

Let me add my name to the list of users for which El Capitan 10.11.2 appears to have resolved the backups with UPS connected issue. Backups resumed on schedule after updating and restarting my Mac with the UPS connected via USB cable.

Yup, backups are now working normal with UPS plugged in. As one of the original poster's, I am very happy. Thank you everyone for your input through this long process and it looks like Apple got it right this time.

I too am happy to report that the issue is fixed for me with this release (10.11.2). Thank you Apple and to all you guys who contributed.

Yes, definitely fixed here, too! Sigh of relief.

Hear hear.

On the bright side, we've probably saved a GB or two's worth of disk space on inactive TM Volumes this last month :-)