Time machine not working after upgrade to Sierra

Try to exclude from backing up: ~\Users\"username"\Library\Mobile Documents. After several days of trying everything, this information from the console helped me. As I understood that folder contains data from iCloud so even if you delete it it will be downloaded again.

A user at my office recently upgraded a mac to SierraOS. As part of my recurring maintenance, I tested a recovery of the backup jobs from our Synology Time Capsule. I was a little rusty, so my process might have been incorrect, but when I tried to restore from the Time Capsule on a test machine, it failed. I had to gain access to the production mac (the one that was upgraded) and although the Synology was still attached and readable from the machine, the backups were failing. When I removed and re-added the Synology as the backup device, Time Machine was able to recognize the Time Capsule and the image that was currently on it, but gave a popup error that essentially said the backup image was corrupt and had to be recreated. After allowing it to recreate, it has run incremental backups without any issues ever since. We use Vipre AV at the moment, so I didn't need to deactivate AV (I know it's not the best for Macs, but we're a mostly Windows environment).

Summary of events (because my paragraphs have a tendency to blur):

1. (Pre-OS upgrade) Verify TM backups are functional.

2. Upgrade Mac to SierraOS.

3. Cannot recover the TM instances.

4. Remove and re-add Time Capsule from TM.

5. Force TM backup job and allow it to recreate the backup image.

6. After first backup job, verify new backup images are recoverable.

7. Followed up after a week and verified they were still working.

Everything in this post happened within the past month.

Interesting. I can't get Time Machine to complete a backup to an external HD directly connected to my MacBook Pro. It'll either start and stall shortly afterwards, or today it spent the whole day "Preparing backup...". It also looks like the diskimages-helper process has been using up an entire core all day. (Seems my Finder isn't responding now either. I'm wondering if something went wrong during my install. Maybe I should try to reinstall).

I am seeing the same behavior after installing Sierra on my MacBook Pro. Time Machine just hangs in the "preparing backup" phase for hours. Activity Monitor shows process "backupd" continuously using a large portion of CPU. My backup disk is hooked directly to my Airport Extreme.

Likewise, since upgrading to Sierra, my Time Machine shows preparing backup but stalls at 1.3mb of about 18gb. Let it run overnight but still doesn't get anywhere. I use a Seagate Backup Plus Slim 2tb external drive which worked perfectly fine before the upgrade. Loathe to re-format as it appears from discussion that doesn't help either.

Same problem here, it gets stuck at "Preparing backup..." mode. It's a 3 TB Apple TC with Airport base station and worked without problem on El Capitan.

The backup is working now, after 30 minutes of "Preparing backup...". The estimated time doesn't match normal time under El Capitan. In addition, the console log messages don't show the normal information it did under El Capitan, meaning HD and file progress. I hope Apple restores this as it's useful to see what it backed up.

Same issue. Time Machine working fine on El Capitan. Now spends ages in "Preparing backup...." backupd is taking 98% CPU and logd 30% at this stage. I have had a successful backup eventually after leaving to run overnight.

I went to the System Preferences Time Machine window and reselected my backup disk. Now it seems to be backing up 20 GB, but at a snails pace compared to El Capitan. After 12 hours it is half done and says it needs another 7 hours.

The current backup (first) is taking 3-4 times longer than El Capitan. It was 10-12 GB's per hour with El Capitan and this is 3-4 GB's per hour. Seems Apple like the keep reinventing the wheel without thoroughly testing it before release.

I moved my backup image to another external hard drive and it seemed to function normally - after the 4 hours to move over 400GB. I put the original hard drive on my Airport Extreme and the Airport Utility wasn't reporting a drive attached at all. I attached the other drive to the AE and it was visible. Maybe it's just that my drive is dying, or that the drive has issues *and* there are Sierra issues. Doesn't explain why the backup worked when I moved it though. I enabled encryption on the replacement drive and when I left this morning it was Preparing Backup.... Hopefully when I get back to it everything will be normal again.

I have the same problem. After 24 hours of "Preparing backup" I cancelled the backup, restarted my 2013 MacBook Air, and tried again. The 2nd time I let the Time Machine backup run for 30 hours. It never left the "Preparing backup" status, so I cancelled it, restarted my computer in the Safe mode, and ran the backup again. This time it only stayed in the "Preparing backup" status for 40 minutes, then, it actually started backing up. After another 40 minutes the backup finished successfully. So, the bottom line is, it will work in the Safe mode, but not in the "regular" mode. There was a Sierra 10.12.1 beta 1 released to the beta testers two days ago. Maybe when it's official it will resolve this problem.

Good luck with safe mode. I've never had good luck with it as it takes a long time and eats memory on the startup. As for the backup, two things I noticed with OS-X 10.12. First the console log no longer writes the information about the progress of the backup it did with 10.11.x. Second, the Time Machine widget no longer works to display information about the progress of the backup, so all you have now is the sytem preferences. Sad. Apple should fix both of these.

same issue - tried multiple solutions but ultimately had to uninstall the antivirus (Avira) - I read others fixed this the same way even if they had other antivirus software

I have two macs so on the air I tried the following with success. I deleted the TM backup, then set up TM as if it was a new computer, it is still backing up without problems. I have Sophos which may be slowing it but I didn't change any configurations. My question is: since it appears the problem is not being able to amend the present backup would renaming the computer so that you start a new backup without deleting the old work so that you can still access the older files and possibly rename again when Apple fixes this problem work?