Timemachine backups failing

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Level 1

8 points

Timemachine backups failing

I got a new mac book pro M1 and connected it to my NAS for time machine backups. The initial backup will start, complete about 20 GB (out of 65 GB). then it will stop and I will get a message saying the backup could not be completed. If I open the Time machine prefrences and click on the info bubble I get the message saying:

"Time Machine could not complete backup to *nas IP address* . An Error occured while copying files."

If I try to select the disk I get this error: " The image macbook pro.sparsebundle is in use. Try ejecting the disk image"

I can use finder to connect to the NAS, no problems there. I have tried rebooting the mac, rebooting the NAS, deleting all the time machine data on the nas, and reformating the nas.

Any ideas?

Thanks.

MacBook Pro (2020 and later)

Posted on Jun 9, 2021 2:04 PM

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Answer 1

Best reply

Grant Bennet-Alder

Level 10

127,567 points

Jun 9, 2021 4:20 PM in response to freerangers

There is an acknowledged problem with Wi-Fi using the 5GHz band on M1 Macs. It appears that the software does not deal well with a split high band 80 GHz channel. When loading gets heavy, it stops working properly.

One User reported that changing the Router settings to 40 MHz channel on 5GHz solved their problem.

Normally, I would recommend that you get an Ethernet adapter. But at the moment, all the aftermarket ones are using an RTL chip that has a different problem, but similar symptoms -- stops working under heavy loads. We think the belkin adapter sold in the Mac store works, but this has not been confirmed.

Both of these issues should be fixed in updates coming soon.

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