Time Machine and Synology

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Level 1

6 points

Time Machine and Synology

I'm on an iMac OS 12.0.1. I've been using Time Machine to backup to my Synology NAS Dual Drive DS218+ successfully for years. Recently it stopped backing up for no apparent reason. Every time I attempt to backup I get the following error message: "The backup disk image "Stanis's iMac.sparsebundle" could not be accessed (error 35)".

There are two strange aspects of this problem:

I was able to backup successfully to this drive a few days ago. As far as I am aware nothing has changed on my iMac system that would have caused the problem.
I have another iMac connected to the same Synology NAS Drive that has no problem with Time Machine backups.

This must have something to do with Time Machine not recognizing the NAS Drive, or deciding that it is read-only, or something, but I can't figure out what the problem is. I've tried a few fixes that have been recommended without success (eg. System Preferences > Sharing, turning on File Sharing and adding the NAS Folder). Any ideas?

iMac 27″, macOS 12.0

Posted on Dec 21, 2021 3:22 PM

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Answer 1

Top-ranking reply

stanis20 Author

Level 1

6 points

Jan 15, 2022 1:19 PM in response to rkaufmann87

Maybe it's a Mac problem, maybe it's a Synology problem, maybe it's both. Anyway, for the benefit of anyone with a Synology NAS who is reading this string and wondering what to try next, the only way I was able to solve the problem was to create two new Volumes on the NAS, one for each iMac, and now Time Machine is working on both of those Volumes.

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Answer 2

au176

Level 1

10 points

Jan 14, 2022 6:53 PM in response to rkaufmann87

Not helpful. My 218+ NAS is completely up yo date, and I have the same problem.

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Answer 3

rkaufmann87

Level 10

143,688 points

Jan 14, 2022 9:20 PM in response to au176

Then it is something with your router or modem setup or some other issue with your Synology setup. We see similar issues all the time where NAS users swear their NAS is fine and their network is fine because their Mac isn't working correctly and when they do some deep diving the issue comes back to the NAS or their network hardware or network setup. We can help on a Mac issue but your network and NAS I think you will need to look for other resources for assistance.

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Answer 4

rkaufmann87

Level 10

143,688 points

Dec 21, 2021 4:52 PM in response to stanis20

Please check with Synology to see if they have some updates for your system, this is generally the problem as NAS developers fall behind on their updates when new OS updates are released.

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Time Machine and Synology

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