Since I upgraded to OS Sierra my time machine has been stuck in "preparing backup" but it never actually does the backup when using the Airport Time Capsule. My second Mac with Sierra backs up fine, but it does not have Sophos on it.
I Stoped Sophos an the backup started immediately.
appears to be a bug.
[locked by: FloSupport at 10:08 PM (GMT -8) on 26 Feb 2019]