Time Machine broken

TM keeps stopping with an error mesage that there is not enough space left to complete the latest backup. Requesting more info shows, as the screenshot attached, that the maths is broken!


There is no option to delete older backups to reclaim space (deleting them manually does not solve the problem either)

Replies

screenshot lost when posting!

It says: backup needs 12.9 Gb but only 62 Gb remining...