time machine backup failed
I am repeatedly getting the message "Time Machine couldn't back up [my] Time Capsule". The details specify that "The backup disk needs 229.01 GB for the backup but only 50.56 GB are available". However, Time Capsule also says "The oldest backups are deleted when your disk becomes full". — So why isn't an
older backup automatically deleted to make room for the next?
MacBook Pro (Retina, 15-inch, Mid 2014), OS X Mavericks (10.9.5), Time Capsule 500GB