Mac Migration Assistant, Time Machine, and the backup agent

Overview

The backup agent ties every backup archive to its source computer with a unique computer ID. When you migrate the agent using a program like Migration Assistant or Time Machine, the file containing this unique computer ID is transferred from the old computer to the new computer. 

As a result, both computers share the same identity. Changes made in the backup agent settings on one computer (for example, the computer name) also update on the other computer. Follow this troubleshooting article to assign your new computer a new ID and differentiate the computers for the backup agent.

Affects

The backup agent on a Mac using Migration Assistant or Time Machine.

Recommended solution

Perform a complete uninstall and reinstall of the backup agent on the new device. 

Related topics

• Computer identities: How they work
• Uninstall and reinstall the backup agent
• What should you back up?