It's supposed to MERGE, BUT Migration Assistant is primarily used to transfer data from one Mac to another when setting up a new Mac or migrating to a different Mac. It can be helpful for transferring files and settings, but it may not be the best tool for recovering a few missing files from a Time Machine backup.
If you have missing files in your Time Machine backup and you want to recover them, you can do so directly from the Time Machine interface without using Migration Assistant. Here's how:
1. Ensure your Time Machine backup drive is connected to your Mac.
2. Click the Time Machine icon in the macOS menu bar (it looks like a clock with a semi circular arrow) or open Time Machine from the System Preferences.
3. Use the timeline on the right side of the screen to browse through backups until you find the date when the missing files were last available.
4. Use the Finder to navigate to the location where the missing files were stored. You can use the Finder's search function to help you locate them if you're not sure where they were.
5. Once you've located the missing files, select them, and then click the "Restore" button to copy them back to your current system.
Using Time Machine directly in this way is a more efficient and targeted approach for recovering specific files or folders compared to using Migration Assistant, which is better suited for broader data migrations.