Sequoia Time Machine Synology NAS keeps disconnecting

I am afraid the problem is on Apple's side.

I have a Synology DS218+ at home, and I have this issue with my MacBook Air recently updated to Sequoia.

I have never had any problems with a Network Time Machine backup (I have three going at the moment). I also don't have Synology anything. It sounds to me that it is on Synology's side.

While checking on different forums, I find someone suggesting to issue the following command in terminal:

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

after few seconds, I got the following:

Timestamp Ty Process[PID:TID]

2024-09-29 18:02:52.849 E backupd[54103:292ab9] [com.apple.TimeMachine:FileProtection] Failed to acquire device lock assertion for '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/iMac-M1/2024-09-29-171018/Data/Users/donato/Library/Containers/com.apple.findmy.FindMyWidgetPeople/Data/SystemData/com.apple.chrono/timelines/com.apple.findmy.FindMyWidgetPeople/systemSmall---2695494529729235827----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"

2024-09-29 18:06:23.246 E backupd[54103:292ab9] [com.apple.TimeMachine:FileProtection] Failed to acquire device lock assertion for '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/iMac-M1/2024-09-29-171018/Data/Users/donato/Library/Containers/com.apple.findmy.FindMyWidgetItems/Data/SystemData/com.apple.chrono/timelines/com.apple.findmy.FindMyWidgetItems/systemSmall---3453820889416213992----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"

There is an issue, "Operation not permitted", with FindMyWidget?

I get the same error on both my macs on Sequoia, an iMacM1 and a MacBookAirM2.

I closed the FindMy Widget on both macs. Let see what happens...

PS: someone else reports that booting into safe mode and then back fixes the problem. Will try this one too...

I encountered the same issue on a 2023 M3 Pro MacBook Pro, typically after computer waking up from sleep. My MBP is connected to the same subnet via both Wi-Fi and a Thunderbolt Ethernet dongle. The backup target is in another VLAN (there is an OPNsense FreeBSD firewall doing L3 routing in between). The TM target is discovered using mDNS (which is repeated by the firewall cross VLANs using mDNS repeater). The Synology is a DS220j running latest DSM.

When the problem occur, the Synology's Resource Manager shows two concurrent connection from my wired IP address to the TM share. I have to kill the older one for TM to work again. This is the workaround I used anytime TM stopped working because of this.

The problem started occurring after upgrading my MBP to 15.0 few weeks ago. I tried eliminating few other probabilities including 1) performance issue with the NAS; 2) L3 firewall state tracking with the pf on my OPNsense firewall when doing inter-VLAN routing and persist idle long connection; 3) concurrent Wi-Fi and wired connection. I come into conclusion that macOS is the most probable one to be blamed.

I have upgraded to 15.0.1 last night and it seems I did not encounter the issue again after waking up the computer this morning. Will continue monitoring the issue.

15.0.1 didn't fix the problem but caused it for me. Time Machine was working fine to a USB drive connected to a Synology NAS in 15.0. After updating to 15.0.1 the problem with the "ejected or disconnected" Time Machine started. Formatting the USB drive didn't help. Only way for me to fix the problem is connecting the USB drive directly to my Mac without going via the NAS.

Unfortunately, 15.0.1 does not fix the issue, at least for me. MacBookAirM2 and Synology DS218+ (but also a WD iCloud at work) and iMac-M1 on an Airport TimeCapsule. If the Mac is not active when the backup is scheduled, the backup fails with the error "Some files were not available...". If TM backup starts when the Mac is active (i.e., if in the meantime, I am working on it), then there is no error, and the backup succeeds.

Prevent automatic sleeping when the display is off in the energy saver panel is active/turned on.

I keep thinking the problem is on the Mac side since everything worked fine with MacOS14, and the problem appeared with MacOS15. I have the same problem with 2 Macs (Air-M2 and iMac-M1) and on 2 different NASs (Synology and WD).

Mike Richards2 wrote:

Is anyone getting this fault on Apple processors?

FWIW. I'm not getting any errors with my 2024 M2 Pro Mac mini (running macOS Sequoia 15.0.1) that I use a Synology DS916+ (running 7.x DSM) for Time Machine.

I was getting similar errors. When I log into the web interface of my diskstation, I can see that when I try to start a TimeMachine backup, it creates a new SMB3 connection to the diskstation. If I delete any previous ones, then the new connection can connect and access the backup and run successfully. If I have multiple SMB3 connections, then the backup fails. I can see connected users (and disconnect ones I don't want) via widgets.

Hi everyone,

Back from vacation hoping that 15.0.1 would fix the issue on my iMac Pro - and no such luck. The firewall is off, but the backups aren't completing - I'm now getting a selection of errors - either Time Machine tells me the sparsebundle is in use or it reports that the drive has disconnected.

I'm chasing Apple who are meant to have got back to me with more information after I sent them a whole bunch of logs, if they have anything useful to say I will share it here.

That thread is a different topic, but yes, related: sometime when a TM backup to a Synology fails because of a network disconnect, the TM disk image becomes stuck in a "in use" state so backup never restarts.

yes, I'm having multiple errors on M1 Max Macbook Pro, mostly around the backup not completing due to disconnection -- also just got a "disk not ejected properly" notification after the backup failed. Periodically the Finder will not access NAS content; this seems to coincide with mounting my iPhone16 and/or having a VM running Windows for ARM.

I am getting this issue with my QNAP TimeMachine Backup and also with RDP sessions disconnecting with a data encryption error:

https://learn.microsoft.com/en-gb/answers/questions/2100561/windows-app-0x407-data-encryption-error-after-upda

Pointing to the Mac Firewall, I turned it off and the errors disappeared both for the backups and the RDP sessions.

There are always going to be bugs in any major release of software like Sequoia, nobody is perfect, not even Apple.

Adrian.

Hats off to you MrHoffman, sir. After seeing your excellent comment I disabled Lulu (from Objective-See) and this Time Machine backup error disappeared.

What's interesting is that the TM backup begins and makes some progress; it just fails part way through. So, the question I'm now asking is whether some my rules are at fault, or whether it's actually the functionality of Lulu itself. It may be one worth raising with Objective-See. I think I will. Will you being doing likewise?

(For others, this exception aside, Lulu is a wonderful app I commend it to those wanting control over inbound and outbound connections on their Mac.)

Thanks again!

It may not be just the Firewall. See the below developer who is concerned about Privacy & Security ---> Local Network settings.

It has broken the app he created

It appears that processes needing access to local network devices are not properly being granted it.

Adrian.

[Edited by Moderator]

These problems are widespread and it may not be related to NAS at all. Many, many users are experiencing inability to maintain persistent connections in 15.0.1. Some are reporting turning off the Apple firewall as working. Do NOT turn off the Apple firewall if you don't have something like Little Snitch installed and properly configured. If you have no choice, please complain to Apple support.

Don't know if this is what did it since I've tried several different things, but I went to Network>Firewall>Options and added the Time Machine app to the list of allowed connections. I've had one successful backup since, but it's such an easy thing to try, I thought I'd post it.