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rmapes Author

Level 1

4 points

Restoring Mac OS from Time Machine

My iMac has been running extremely slow and I'm thinking of erasing and reinstalling to try and speed it up. Currently, my Time Machine backs up my internal drive, as well as one additional external drive. If I transfer from a time machine back up once I reinstall, will the backed up files from my other external hard drive upload on my internal hard drive?

iMac 27", macOS 10.14

Posted on Jun 21, 2019 12:24 PM

Top-ranking reply

Tesserax

Level 10

152,302 points

Posted on Jun 21, 2019 1:19 PM

I believe the following will be true after using Recovery Mode to first erase your Macintosh HD drive and reinstalling a clean copy of macOS. Then restoring from a Time Machine backup:

After the installation of a clean copy of macOS has completed, and upon the first restart of your Mac, you will be presented with the Setup Assistant. From there you will have the option to restore your iMac from a backup.
Since only the Macintosh HD was affected, there shouldn't be any reason to restore a backup to the external drive.

Ref:

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Restoring Mac OS from Time Machine

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