Karenms wrote:
It initiates the backup, but is ejected from the MacBook Pro 2013, running MacOS Catalina 10.15.3.
The drive is a Seagate Expansion 1 TB portable drive. I have it partitioned with 700 GB available for the backups. The last backup was January 2020 and it was backing up fine up to that time. Thanks for the help.
Sounds like the drive is failing.
From Disk Utility> run the First Aid on your external drive— If errors are found and repaired, run again until no errors reported
Repair a storage device in Disk Utility on Mac - Apple Support
You can always try erase/reformatting the drive in an effort to revive it—and start over.
3-2-1 Backup Strategy: three copies of your data, two different methods, and one offsite.
Boot clone https://discussions.apple.com/docs/DOC-10081
How to use Time Machine to back up or restore your Mac: https://support.apple.com/en-us/HT201250
Use DiskUtility Restore feature https://support.apple.com/guide/disk-utility/restore-a-disk-dskutl14062/mac
note: >System Preferences>Security & Privacy >Privacy>Full Disk Access
unlock the padlock, press the + button and add Disk Utility