2020 iMac: external start up with High Sierra?

Setting up my new 2020 27" iMac with catalina, and am hoping to occasionally use an external SSD, a copy of my previous High Sierra iMac, so can run older programs (looking at you Adobe). Possible?

Thanks! John

Posted on Aug 21, 2020 03:57 PM

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dialabrain

Level 10

133,529 points

Posted on Aug 21, 2020 04:12 PM

No.. High Sierra nor Mojave will boot on an iMac that shipped with Catalina.

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Top-ranking reply

dialabrain

Level 10

133,529 points

Aug 21, 2020 04:12 PM in response to John Phillips10

No.. High Sierra nor Mojave will boot on an iMac that shipped with Catalina.

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2020 iMac: external start up with High Sierra?

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