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boghav Author

Level 1

4 points

os 10.12 no longer sees a TB drive that has been loaded with os 12.0.1

loaded Monterey 12.0.1 onto a Lacie TB SSD drive which WAS working with my main Mac Pro OS of 10.12. Wanted to update the os for newer programs while maintaining my legacy system apps in 10.12.

Made the Lacie a boot drive by changing the startup drive to the Lacie and downloading and installing the Monterey-which is functioning at this point.

All worked well until I tried to restart Mac using the Lacie TB drive as the startup drive after switching the bootup back to the 10.12 os. The Lacie is not recognized on the desktop in os10.12.

Mac Pro

Posted on Nov 20, 2021 1:11 PM

Top-ranking reply

a brody

Level 10

84,005 points

Posted on Nov 20, 2021 2:46 PM

That's correct. 10.12 is too old to see Apple's APFS format. Any solid state drive will automatically format as APFS on 10.13 or later, and 10.14 or later can't install 10.14 or later on solid state drives unless they are formatted APFS. 10.13 is the earliest Mac OS supported APFS. 10.2.3 through 10.5.8 only recognize Apple Partition Map HFS Extended Journalled. And 10.6 or later recognizes GUID on Intel Macs as well.

If you need to boot off an older drive to see a new Mac, consider using file sharing alternatives over a network.

AnyDesk has older versions, Teamviewer has older versions, and Apple includes in

System -> Library -> CoreServices -> Applications -> Screen Sharing for accessing Macs that have screen sharing turned on.

https://mbsdirect.com/mbs-blog/article-use-the-macrsquos-built-in-screen-sharing-to-provide-remote-help

The nice thing about screen sharing is the Mac that runs it can drag files out of the screen sharing window onto its folders, or vice versa enabling file transfers as seemlessly as on the Mac file system itself.

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os 10.12 no longer sees a TB drive that has been loaded with os 12.0.1

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