Time Machine Backup Fails Repeatedly macOS 10.13.6
I installed the Security Update 2018-002 for macOS High Sierra Version 10.13.6 on 11/6/2018 and have NOT been able to complete a Time Machine backup since.
Keep getting "Backup Failed. Time Machine couldn't back up to Iomega HDD" message. It takes many minutes in "preparing backup" then finally starts backing up, but never finishes.
Most recent attempt this evening 11/20/2018:
8:42 PM - Started Time Machine backup, in "preparing backup" for 66 minutes
9:48 PM - "Backing up: 71.8 MB of 16.64 GB" and "Calculating time remaining..."
9:55 PM - "Backing up: 907.3 MB of 16.64 GB" and "About 5 hours remaining"
9:56 PM - "Backing up: 987.0 MB of 16.64 GB" and "About 4 hours remaining"
9:57 PM - "Backup Failed. Time Machine couldn't back up to Iomega HDD"
My last successful backup was 11/5/2018, the day before I installed the update taking me to macOS Version 10.13.6.
I dare not move to Mojave until I have a Time Machine backup for my current system.
Help please!
Mac Pro, Other OS, macOS High Sierra Version 10.13.6