Time Machine backup on macOS Sequoia cannot be completed

OK, so I tested the 2016 trick about disabling the IO throttling (sudo sysctl debug.lowpri_throttle_enabled=0) and that helped!

First backup after that on my MacBook Air took 11 minutes to prepare (before, it was >1h) and the backup then took about 15 minutes including clean up.

Second backup right after took 7 minutes to prepare and 4 minutes for backup and clean up.

I would say that is back to pre Sequoia performance. Great!

One can make this survive reboot by adding "debug.lowpri_throttle_enabled=0" to "/etc/sysctl.conf".

I also have from 1 year ago "/etc/nsmb.conf" with this content on the MacBook Air:

[default]

signing_required=0

I'll see when I try the throttling trick on my Mac mini if that makes any difference for TM because I do not have that file there.

I fixed this by removing the (NAS) drive from Time Manager and adding it again. When I re-added it, I got the message "checking capabilities of drive..." and it chuntered away for a few minutes before telling me that the drive was not encrypted, was I sure? I said I was and it's trundling along nicely now.

Although I had initial success with this fix, it quit working for me after a couple of follow up back ups. I have been out of town for several weeks without access to my NAS but keeping up with all Sequoia partial updates. When I returned home I deleted my laptop's backup file on the NAS and re-ran Time Machine. After a successful backup to the NAS, the updated backups have been running just like they did pre-Sequoia. I suspect Apple has made a change in Sequoia Time Machine with one of the updates since that is all that has changed for me.

After sending the Prime Video app to the Trash yesterday, the TM backup ran successfully last night. I am surprised that TM could be prevented from copying files. I installed TM originally in the admin user account and backupd and backupd-helper both have root level access.

I couldn’t make the Time Machine work with 15.0 or 15.0.1, so I used Terminal to add the code snipped from keithfromsalado: "sudo rm -f /etc/nsmb.conf” and restarted the Time Machine set up. It worked perfectly. Thank you, keithfromsalado!!

I tried the terminal command stated by keithfromsalado: "sudo rm -f /etc/nsmb.conf” and restarted my Mac. I tried Time Machine again and it worked! This command line completely resolved my Time Machine issue. Thank you, keithfromsalado!!

As I posted earlier, I was unable to successfully make a TM backup session after installing Sequoia. Today however, I was able to successfully back up after turning off the firewall on my MacBook. I then updated to 15.1 and successfully backed up with the firewall turned on. Can’t really explain this, but Time Machine now works properly.

I have a Mac mini M2 running Sequoia 15.2. By switching OFF the Mac firewall then rebooting the Mac mini and then switching on the firewall again and adding Time Machine as a permitted app I can now back up to WD My Cloud EX2 Ultra using Time Machine via a 25 port LAN switch. Thank you to all who gave me advice, support and encouragement.

Pi-Jay,

Go into the /Users/your user account/Library/Safari you can get here by going to the Go Menu and holding down the Option Key Select Library. When you click on the History.db file press Command I to get the Information on the file make sure that your account is listed in the Sharing and Permissions section, you may need to add it in and set the Privilege Read and Write.

Note: You need to click on the Lock in the lower right hand corner before changing the Sharing & Permissions

With 15.3 my problem resolved. All works fine now.

I, too have had problems with TimeMachine backing up to a Synology NAS server since upgrading to Sequoia (15.0 or 15.0.1, don't know which). Problem continues under 15.1.

I tried some of the other suggestions - (1) turning off Firewall, but (2)mainly removing the backup drive in TimeMachine settings, deleting my old backup folder on the NAS, booting into SAFE Mode and pointing TimeMachine settings into a newly created NAS folder share and backing up (successfully). Then doing a "normal" rebooting. Time Machine successfully backups as long as I keep my Mac Studio active. But whenever I leave my Mac and it hibernates, it always fails. But once I get back onto my Mac and it is "active", TM successfully backs up.

I have already gone into System Settings : Energy and enabled "Prevent automatic sleeping when the display is off" and disabled "Put hard disks to sleep when possible". This has not prevented the backup failures when I am away from my Mac.

I will try the suggestion above to change my power management.

This community was helpful in giving me paths to finding a way to do a TimeMachine backup on my MBP 13" M1 2020 MacOS15.3. What finally worked was disabling the Apple Firewall. I kept the Norton Firewall active for some protection while the Apple firewall was inactive. Backup took about the same amount of time (2 hrs) to complete as it has in the past. Adding TimeMachine.app to the list of apps that were allowed to be accessed in SystemSettings/Network/Firewall didn't work. I also spent a lot of time trying to find the file that TimeMachine identified as the file blocking completion of Backup. Spotlight was not helpful and so I went down numerous blind alleys in my unsuccessful search. I thought by eliminating this file, Backup might work. It seems like the best permanent fix lies with Apple. Good luck to you!

I had the issue and first I turned the firewall off and it worked.

Afterwards I saw one could refine the firewall rules and I added the firewall to accept all incoming connections with TimeMachine.

I am on macOS 15.2 MacStudio M1, with the TM storing on a thunderbolt attached ssd. Using the command:

log show --info --style compact --predicate '(subsystem == "com.apple.TimeMachine") && (eventMessage like[cd] "Failed * acquire device lock assertion*")' --last 24h

I see the following TM errors when the machine is locked (I've TM setup for hourly backups):

2024-12-18 11:49:25.077 E  backupd[250:1e72603] [com.apple.TimeMachine:FileProtection] Failed to proactively acquire device lock assertion on lock state change (deviceIsLocked), assertion state: <dropped>, error: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"
2024-12-18 11:50:13.608 E  backupd[250:1e726d1] [com.apple.TimeMachine:FileProtection] Failed to acquire device lock assertion for '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/maccback/2024-12-18-114912/Data/Users/rdm/Library/Containers/com.apple.findmy.FindMyWidgetPeople/Data/SystemData/com.apple.chrono/timelines/com.apple.findmy.FindMyWidgetPeople/systemSmall---1238357860398622014----164.00w--164.00h--20.00r--0f--0.00t-0.00l-0.00b0.00t.chrono-timeline' (assertion state: <dropped>), error: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"
2024-12-18 11:50:17.473 E  backupd[250:1e726d1] [com.apple.TimeMachine:FileProtection] Failed to acquire device lock assertion for '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/maccback/2024-12-18-114912/Data/Users/rdm/Library/Metadata/Assets/com.apple.MobileAsset.SpotlightResources.plist' (assertion state: <dropped>), error: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"



These errors don't appear when the machine is not locked. I have indeed one FindMy People widget setup. Do other people find something similar?

Cheers, Fons.