I have had some problems with my Time Machine backups this week.
I am running Mac OS Sierra (10.12.6) on an iMac 2017 and am using an AirPort Time Capsule for the Time Machine backups.
On Tuesday, Time Machine stopped perform its backups and displayed the following message:
**Time Machine completed a verification of your backups on . To improve reliability, Time Machine must create a new backup for you.
Click Start New Backup to create a new backup. This will remove your existing backup history. This could take several hours.
Click Back Up Later to be reminded tomorrow. Time Machine won’t perform backups during this time.**
Since I basically had no choice, I started the new backup. This created a brand new backup and everything seemed to be fine.
Today, Time Machine is giving me the following notification:
**Time Machine couldn’t complete the backup to <diskname.local>.
The backup disk image “/Volumes/Data/Harddis.sparsebundle” could not be accessed (error 21).**
I can access the Time Capsule from a Finder window, and I can enter Time Machine and navigate to the most recent backups. However, going back too far (more than a few backups) seems to cause a “waiting” message to appear.
Any ideas on the cause of this? I fear that my Time Capsule has given up the ghost.