My Time Machine Backup (to an Apple Time Capsule) failed with the message:
Time Machine could not back up the disk “Macintosh HD — Data” because it is nearly full.
Note that this does not appear to refer to the backup disk (which is empty) but to the source disk. The source disk has 1 Tb free... How much space is needed?
Time Machine says 1.92TB free; 2.25 TB used
Can you check this again? The largest Time Capsule disk is 3 TB. 1.92 TB free + 2.25 TB used = 4.17 TB.
When you reformatted the Time Capsule, did you you choose the Zero Out Data option for the erase?
If you chose the Quick Erase option, the disk was not really erased at all. This type of erase simply allows new data to overwrite the old data.
Worth a try if you have not done this, but since Apple discontinued the Time Capsule over 3 years ago.....and.....Big Sur tries to back up to the Time Capsule using a different format than the Time Capsule, I would not look for Apple to move quickly for a "fix".
The Time Capsule can only be formatted in Mac OS Extended (Journaled), but Big Sur formatted your Mac in a different format called APFS. Wonder what could possibly go wrong with backups.
I don't think Apple is going to spend any time trying to fix a product that was discontinued more than 3 years ago. But, I could be wrong.
Time Machine says 1.92TB free; 2.25 TB used
Can you check this again? The largest Time Capsule disk is 3 TB. 1.92 TB free + 2.25 TB used = 4.17 TB.
When you reformatted the Time Capsule, did you you choose the Zero Out Data option for the erase?
If you chose the Quick Erase option, the disk was not really erased at all. This type of erase simply allows new data to overwrite the old data.
Worth a try if you have not done this, but since Apple discontinued the Time Capsule over 3 years ago.....and.....Big Sur tries to back up to the Time Capsule using a different format than the Time Capsule, I would not look for Apple to move quickly for a "fix".
The Time Capsule can only be formatted in Mac OS Extended (Journaled), but Big Sur formatted your Mac in a different format called APFS. Wonder what could possibly go wrong with backups.
I don't think Apple is going to spend any time trying to fix a product that was discontinued more than 3 years ago. But, I could be wrong.
Big Sur is having loads of problems with Time Machine, so if you have recently updated your Mac, there is that.
Are you trying to run a backup for the first time, or have backups been running OK up until now and the message has just appeared?
If you click on the Time Machine "clock" icon at the top of the screen and then click on Open Time Machine Preferences, what is the message that you see concerning available space on the Time Capsule? It will read something like........xxxx TB available. What is the message that appears when you do this?
On your Mac......
Open Disk Utility (Finder > Applications > Utilities > Disk Utility
Click to highlight Macintosh HD - Data on the left panel and then look over in the space to the right to see the info about the disk
What is the info that do you see for......
Used?
Other Volumes?
Capacity?
Available?
Thanks for that.
Macintosh HD - Data says 842GB free
Time Machine says 1.92TB free; 2.25 TB used; 28.57GB other volumes.
I suspected an issue with a Big Sur update and you have sort of confirmed this. It's just appeared in the last week or so after years of successful Time Machine operation. I guess I wait till they fix it. I've tried reformatting the Time Capsule but to no effect (and rightly so since it's not complaining about that).
Apologies… I mistyped the information.
Macintosh HD - Data says 842GB free; 2.25 TB used; 28.57GB other volumes.
Time Machine says it has 1.92TB free;
Hadn’t realised the Timecapsule was discontinued. I will both try the re-formatting and start looking for a new backup disk. I agree with you on the likelihood of a software fix.
It's your call, but if the Time Capsule is more than 5 years old, both the internal power supply and hard drive are now "suspect", so I would not keep any data on the Time Capsule that I could not afford to lose......unless......I was also backing up to another hard drive.
Having taken a step back from fixing the immediate problems to consider how the issue evolved, I think the time machine/capsule issue is implicated in the failure of various aspects of my iCloud syncing: random file loss; keychain issue; photos and videos missing which appear (so far anyway)to have gone away when the capsule was disconnected. Not exactly the situation you want to be in when your backup fails. Can't prove it in the short term, and correlation is not causation, but it's put me off restarting a Time Machine backup (which was probably overkill for my current situation).
Time Machine Backup failed
