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Time Machine

Have started receiving the message "Backup Not Completed Time machine couldn't back up to (name of my external drive)" where I've been backing up for a couple of years. When I click on "details" I get the message "An error occurred while preparing the backup"


I'm running macOS Monterey 12.1. Was receiving the error a couple of months before upgrading to Monterey. I have a manual workaround using terminal. After doing the workaround/cleanup Time Machine will function normally for a period of time. The period used to be a couple of weeks, but not seems to be every couple of days.


Posted on Jan 21, 2022 6:18 AM

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Posted on Jan 21, 2022 8:49 AM

Have you tried running First Aid on the backup drive?

Sounds like there is some underlying problem with the drive which might be fixed by running First Aid.

2 replies

Jan 25, 2022 1:12 PM in response to Barney-15E

I back my iMac up on two separate external drives. Originally it was just one external, and that’s where the trouble started. About two weeks ago I also started backing it up to a NAS drive. The problem I described then happened with both drives.

Following your suggestion, I ran First Aid on the first external. It couldn’t complete. I then reformatted the drive and told Time Machine to return to backing up to both external drives. The first backup took about 20 hours and finished on the 23rd. Time Machine has now been alternating the hourly backups without problems for a couple of days. My fingers are crossed that the problem is resolved.

Thanks for your suggestion.

Time Machine

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