I have had a couple of warnings like this in the past week. My MacBook Air only has a 250Gb HDD, and my backup drive has 4Tb, so space shouldn't be an issue. I thought that T.M. automatically deletes older backups to make space for new ones, itself. I have about 27 previous backups, so I can delete older ones myself, but...
Time Machine could not back up the disk "Macintosh HD" because it is nearly full.
If you think the wording in that dialog could be improved upon you're not alone. The word "it" in that sentence (the object pronoun) refers to the object "Macintosh HD". It can't possibly refer to anything else, because Time Machine is not something that can become full... but you would need to be an expert in Apple-speak to fully comprehend that fact.
If it were to say "Macintosh HD" is nearly full then it would be abundantly clear what the problem is. If you were to somehow interpret that statement correctly despite the manner in which it was (poorly) written, then you would know how to fix it — which the next sentence is tries (and fails) to state:
Delete some files on "Macintosh HD" and try again.
🙂
Time Machine could not back up the disk "Macintosh HD" because it is nearly full.
If you think the wording in that dialog could be improved upon you're not alone. The word "it" in that sentence (the object pronoun) refers to the object "Macintosh HD". It can't possibly refer to anything else, because Time Machine is not something that can become full... but you would need to be an expert in Apple-speak to fully comprehend that fact.
If it were to say "Macintosh HD" is nearly full then it would be abundantly clear what the problem is. If you were to somehow interpret that statement correctly despite the manner in which it was (poorly) written, then you would know how to fix it — which the next sentence is tries (and fails) to state:
Delete some files on "Macintosh HD" and try again.
🙂
Please review If you can't back up or restore your Mac using Time Machine - Apple Support.
I thought that T.M. automatically deletes older backups to make space for new ones, itself.
Correct.
I have about 27 previous backups, so I can delete older ones myself, but...
Actually, we can no longer do that, and it was a bad idea back when we could, because Time Machine automatically deletes older backups to make space for new ones. If you somehow managed to delete previous backups manually in the past that is likely to be the reason. Erasing the backup drive is the only way to make TM work again.
Ok thanks. Please take a screenshot of that message, and post it in a reply.
Instructions for capturing, editing (if necessary) and posting a screenshot to this site are in the Appendix of Writing an effective Apple Support Communities question - Apple Community. Scroll down to Screenshots (Mac).
Hmm, I removed my backup drive from T.M., erased the backup drive, added it and tried again. The issue unfortunately remains: an error tells me that the disc is nearly full (it's not). So I tried with a different (erased) drive. Same thing, not enough space.
I will read through that Apple document again, but I would be grateful for more assistance,
That's great John, thank you for your reply.
Thanks. I hope that screenshot is not too large.
Pretty much the perfect answer, thank you again. I did at one point think that the wording of that dialog is somewhat unclear.
Time Machine unable to complete backup
