Remove redundant backup from Airport Time Capsule without doing a full reset

[Alwyn]

Having at last upgraded my newly acquired 2017 iMac to Big Sur and migrated everything else from 2014 iMac, I now need to backup to my A1409 Time Capsule. Owing to a mistake I made earlier, the system isn't recognising previous backups. This means that it wants to do a complete backup for which there isn't apparently enough room. As it has a 2TB capacity this is rather surprising.

In the last resort I believe a reset would remove the backup but it would also mean having to do a full new setup which I would like to avoid.

Presumably because the Time Capsule connects wirelessly or with an Ethernet connection it doesn't seem to show up in Disk Utility.

 

[MacInWin]

TM probably thinks your iMac is new because of the upgrade, so it won't show some other machine's backups (Even though it is the same hardware). What "mistake" did you make? Maybe that's fixable. The fact the TC is 2Tb really has nothing to do with the backup, it's how much FREE space is on it that is critical. It could be 100 zillion petabytes, but if it doesn't have free space for a backup, you can't use it as it is. As for the drive not showing in Disk Utility, you are correct about why. None of my NAS devices show in Disk Utility. I don't have a TC, just an Airport, but does the AirPort Utility let you manage the TC?

 

[Alwyn]

TM probably thinks your iMac is new because of the upgrade, so it won't show some other machine's backups (Even though it is the same hardware). What "mistake" did you make? Maybe that's fixable. The fact the TC is 2Tb really has nothing to do with the backup, it's how much FREE space is on it that is critical. It could be 100 zillion petabytes, but if it doesn't have free space for a backup, you can't use it as it is. As for the drive not showing in Disk Utility, you are correct about why. None of my NAS devices show in Disk Utility. I don't have a TC, just an Airport, but does the AirPort Utility let you manage the TC?

To an extent the Airport Utility does but the options as far as deleting anything appears to be ‘erase’. I haven’t tried it because I am not sure what it is erasing. Is it the same as resetting via the reset button?

 

[Alwyn]

RESOLVED. The erase option doesn’t change the basic settings. It only erases the backups on the disk. There is a basic ‘insecure’ option followed by several options. It would be useful to understand why the most secure option is necessary as it would take about 2 weeks via WiFi.

 

[MacInWin]

It would be useful to understand why the most secure option is necessary as it would take about 2 weeks via WiFi.

If you are an international spy, or a mafia member, and have important stuff on the backup, those more secure wipes can make it harder for an enemy to recover anything from the drive. But if you are just a user, like most of us, it's totally overkill.