Question: How to reformat OS Catalina external 2 drives into one?

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Girshon Rutstein

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(409 points)

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Question: How to reformat OS Catalina external 2 drives into one?

OS Catalina created 2 external HD and HD Data? How to reformat and merge them into one, like I had before? Thanks.

iMac 27", macOS 10.13

Posted on Apr 20, 2020 12:04 PM

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Answer 1

BDAqua

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Apr 20, 2020 12:12 PM in response to Girshon Rutstein In response to Girshon Rutstein

Catalina does that on it's own though generally it hides one, the first one is a Read Only Partition with the OS on it.

Apr 20, 2020 12:12 PM

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Answer 2

Girshon Rutstein

Level 2

(409 points)

Desktops

Apr 20, 2020 12:17 PM in response to BDAqua In response to BDAqua

Well, generally it hides, but on my desktop there are two of them. And Disk Utility is showing 2 of them as well. Which one do I erase. Because I can not erase them both at one time. If I erase the main one will Data disappear?

Apr 20, 2020 12:17 PM

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Answer 3

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BDAqua

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Apr 20, 2020 2:39 PM in response to Girshon Rutstein In response to Girshon Rutstein

Yes, if you erase then all data will be lost.

You have to select the whole drive above Mac HD & Mac HD Data, usually in Disk Utility's View menu>ShowAll devices.

https://support.apple.com/guide/disk-utility/partition-a-physical-disk-dskutl14027/mac

Bombich Software, makers of Carbon Copy Cloner, has a more detailed explanation on their blog. (And note that if you mount a Catalina drive in Mojave, both volumes mount correctly, but appear separately and unlinked.)

Apr 20, 2020 2:39 PM

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Answer 4

Girshon Rutstein

Level 2

(409 points)

Desktops

Apr 20, 2020 2:42 PM in response to BDAqua In response to BDAqua

Thanks, but I did it very easy way. I clicked on minus on Data disk in Disk Utility and erased the main drive. That's all.

Apr 20, 2020 2:42 PM

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Answer 5

BDAqua

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Apr 20, 2020 2:47 PM in response to Girshon Rutstein In response to Girshon Rutstein

Ok, every working then?

Apr 20, 2020 2:47 PM

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Answer 6

Girshon Rutstein

Level 2

(409 points)

Desktops

Apr 20, 2020 2:52 PM in response to BDAqua In response to BDAqua

Thanks, BDAqua,

Yes, not without help of Apple senior advisor, who helped a few people like me before. Users who went back to Mojave or High Sierra after trying OS Catalina.

Apr 20, 2020 2:52 PM

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Answer 7

Solved

BDAqua

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Apr 20, 2020 3:00 PM in response to Girshon Rutstein In response to Girshon Rutstein

OK, stay well. :)

Apr 20, 2020 3:00 PM

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Answer 8

Girshon Rutstein

Level 2

(409 points)

Desktops

Apr 20, 2020 3:18 PM in response to BDAqua In response to BDAqua

I consider that you helped me to solve the issue. Solved!

Just curious, how come I never get any credit, like solved or help from other users. And I did help a few dozen times in the past, not that I really care to get recognition. As long as I did help, that makes me feel good.

Apr 20, 2020 3:18 PM

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Answer 9

BDAqua

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Apr 20, 2020 3:33 PM in response to Girshon Rutstein In response to Girshon Rutstein

Oh boy, it's tough, I'd say overall I only hear back from about half the the people I reply to, 50% of the ones that do never award points, 10% award the points to themselves, & I'm unable to solve some & of course other helpers may solve it instead of me.

Back when it was easier to get points awarded AND the forum was much more useful, I scored about 0.089 points per post... so don't feel bad. :)

Apr 20, 2020 3:33 PM

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Question: Q: How to reformat OS Catalina external 2 drives into one?

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Question: How to reformat OS Catalina external 2 drives into one?