I've run Yosemite for some time now, this issue is recent. My assumption has always been that Time Machine autonomously overwrites old backups once your time capsule is full.
So my question is :
How do I resume normal Time Machine backups without having to manually erase old backups. I know I can delete files from Time Capsule
Running:
10.10.2
Time Capsule :
461 GB of 2TB available…backup error is
The backup disk needs 536.69 GB for the backup but only 460.78 GB are available. Select a larger backup disk or make the backup smaller by excluding files.
Best Answer
This somewhat of a long shot, but it sounds a little like you may have changed something on your disk. "Invisible" actions like changing file permissions or HFS+ compressing files will cause TimeMachine (TM) to assume that the files have changed and need to be backed up. Another scenario would be that the UUID of your hard disk changed. This article lists some further possibilities. So to answer your questions:
I suggest you try the following:
diskutil list
andcom.apple.backupd.SnapshotVolumeUUID
on your TM disk (not too sure about the file name, because I use sparsebundles)/Library/Preferences/com.apple.TimeMachine.plist
sudo tmutil inheritbackup /Volumes/myTM/Backups.backupdb/myMac
orsudo tmutil associatedisk -a / /Volumes/myTM/Backups.backupdb/myMac/myDisk
Note that you might loose your entire backup. Please make a copy of your Time Machine backup.