Sierra and Time Machine

Thank you so much for putting this out!

I tried so many things but your guide was what made it work finally. It took my computer longer than a day to complete the back up, however I'm glad this problem with Sierra is behind me now.

Just got off of 90 minutes of technical support with Apple.

Sierra broke the way that Time Capsule sparsebundles are opened. If you navigate to your Time Capsule volume and open Time Machine backups, you should see a sparsebundle for each machine you back up. Double click on one.

If you get an error that the application "DiskImageMounter.app" cannot be opened (-36), then you've been bitten by this known issue.

I found that you can still do level 0 backups by hand (that is, you can start over with backups—it's only the incremental backups that stall for me). This is not a realistic solution in the long run, but will at least let you do a backup.

It also seems to be Time Capsule specific—I can still do incremental backups to another drive.

They said that this should be fixed in OSX 12.3

I discovered that Kaspersky Internet Security was the problem after upgrading to Sierra from Mavericks. As soon as I turned off protection, the backup time plunged (about two hours to do initial backup 350 Gbytes of data).

Solution: You can tell Kaspersky to ignore TM. Here is the official solution:

“STEP 1: Please add this to the Trusted Zone in Kaspersky to exclude it from scans:
Open Preferences: http://support.kaspersky.com/us/12555
Click on ‘Threats’ along the top of the preferences window
Click the ‘Trusted Zone…’ button near the bottom right.
Click the + button on the bottom left.
Locate what you are looking to exclude, and click the ‘OK’ button.
Close out of the Preferences window, and test if the issue persists”

Presumably this approach will work for other anti-virus software.

Possibly related issue... I'm curious if 10.12.3 solved your issue or not.

I'm using OS X Server on a Mac Mini and 2 external USB drives to back up a couple of Macs. Working just great under El Capitan for months. Upgraded the clients (but not the server) to Sierra and within a week, the backup failed. For other reasons, I downgraded to El Capitan and again experienced problem-free backups for several weeks. Around the time 10.12.2 released, I decided to try Sierra again. Once again, I needed to create a new backup from scratch within a week.

I created a new backup, and while I'm having no troubles completing initial backups, eventually the backups fail verification and I must start a new backup (the "To improve reliability, Time Machine must create a new backup for you" error.) The disks check out fine when I check them for errors. I do believe the backups are failing/corrupted, but I don't believe that my hardware is the problem.

For the moment, I'm backing up to 2 different disks so that when one fails verification, I've still got a backup on the other, for each computer, but I'm unable to keep more than ~5 - 7 days of backups going due to the repeated failures. Backups fail on either drive, either client, eventually, always within a week or so.

I upgraded to 10.12.3 the day it released with hopes it would solve this issue but I just had to "create a new backup" for my Macbook Pro. So for anyone experiencing the "To improve reliability..." errors, 10.12.3 is probably not going to fix it for you.

Again, I'm certain this isn't a hardware problem as I'm experiencing it quite regularly under 10.12.2 and 10.12.3 and had previously experienced it with 10.12.1 before downgrading and subsequently having trouble-free backups again. El Capitan works fine with this (supported) configuration and Sierra does not.

I too had this issue.

I updated to High Sierra yesterday and today started backup which was quite painful, as first it took time machine hours to prepare backup and then years to back up for just 125 GB backup..which never happened. Even formating the external drive for time machine.

I have a MB Pro early 2015, with Bitdeffender Anitivirus as well as Malwarebytes installed on it.

I disabled both and stopped indexing of the backup drive.

Started manual backup and it was quite pretty to see it tugging along at good speed.

Now it is showing about an hour for backup to complete.

May be it is because of the first back up as I had previously erased the disc.

I too had this issue.

I updated to High Sierra yesterday and today started backup which was quite painful, as first it took time machine hours to prepare backup and then years to back up for just 125 GB backup..which never happened. Even formating the external drive for time machine.

I have a MB Pro early 2015, with Bitdeffender Anitivirus as well as Malwarebytes installed on it.

I disabled both and stopped indexing of the backup drive.

Started manual backup and it was quite pretty to see it tugging along at good speed.

Now it is showing about an hour for backup to complete.

May be it is because of the first back up as I had previously erased the disc.

Hope it may help

I agree with your suggestion it is down to TM priority, given the differing solutions given. In my case I resolved it by disabling wifi during backups. TM starts backup up instantly after wifi is disabled. This is certainly no fix, just a work around. Clearly Apple have broken TM by giving it a reduced priority. I hope Apple are aware of this, and will patch this at some point. Is anyone on the forum feeding all this back to Apple? Would love to contribute but not sure how.

After the latest backup today, the TM is showing those signs of slowing again..hours taking prepariing the backup Nd finally back stopping halfway through.

so I followed the old regieme of:

1. Deactivating antivirus temporarily

2. Disabling Wifi & Blue tooth

3. Disabling the gatekeeper in security & prefrences

4. Disabeling automatic backoff.

Now the TM tugging along and has backed up about 20GBs of Data out of 97 plus in about 20 minutes.

I really am at a los as to why this is happening.

Anyone has suggestions..?

Also if Apple people are aware of these issues..? God Knows only.

I am having Time Machine issues with High Sierra. Time Machine rarely does a sensible incremental backup anymore, it does full backups almost all the time. I can't determine why. I have four Time Capsules that I back up a MBP to in sequence. It has worked fine for years, until High Sierra. Now it RARELY does a sensible backup of a couple MB, and just about every back up is 150 GB - 210 GB. They take hours each, and my system seems to be constantly backing up. I am not creating that much new content. I browse, write a couple texts, a couple short emails, and I have Time Machine set up to not back up plenty of library stuff, music, and overhead type stuff that can easily be restored by other means. That's it. My Time Capsules are filling up with all of whatever Time Machine keeps putting on there.

Any ideas?

I'm having the same issue. Hopefully we can get some assistance regarding this issue.

I had the same issue. It was on "Preparing Backup" for hours. I just stopped the backup and restarted it and now it's working! Slow.. but working!

Same problem here...

Yesterday...

"Preparing Backup" took many many MANY hours, - than backup finally started...

Also took many hours...

This morning, after restarting my iMac Time Machine was hanging again...

"Preparing"...

After an hour Tim Machine finally starts up...

Copying...

But... very very slow...

Jur Kuipers, The Netherlands

Hi Don (@arizonadonn),

Did it help?

Just asking...

Jur Kuipers, The Netherlands.

I solved my slow-Time Machine problem in macOS Sierra!

After Time Machine (again) took ages to backup I stopped Time Machine by unchecking "Automatic backups" in System Preferences/Time Machine (unchecking the new little "check-box").

After this abrupt stop I again checked that little check-box "Automatic backups" in System Preferences/Time Machine.

Then activated "manual backup" (starting backup) by activating Time Machine via menubar.

The first Time Machine (TM) was slow again, but after stopping and restarting a few times (stop and restarting by check-uncheck/System Preferences and starting up by "manual backup"/menubar).

TM then copied as it should.

...But then after successful copying "Backup thinning" took forever... ("opschonen" in Dutch).

Stopped "Backup thinning" by unchecking Automatic backups" in System Preferences/Time Machine.

Then activated "manual backup" by activating Time Machine via menubar (after I again checked "Automatic backups" in System Preferences/Time Machine).

Now "Backup thinning" - when necessary - completes the TM-backup successfully.

TM is working fine (and fast) now (automatic hourly backups).

Perhaps this is helpful?

It worked for me.

Best regards,

Jur Kuipers, The Netherlands