Running iMac from External SSD, Erase internal HD?

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Running iMac from External SSD, Erase internal HD?

I'm running my late 2012 iMac from a Samsung external SSD, computer is running pretty well, much faster, sometimes it restarts but for the most part it good. Should I erase the internal hard drive? I ask this because when OS updates come up, they want to install in the internal hard drive and since that drive is very slow, it just jams things up for an hour or so. Alternatively, is there a way to prevent updates from installing into the internal hard drive? I find it hard to believe that updates install to the internal HD since the Mac is not running off that HD?

iMac 21.5", macOS 10.15

Posted on Dec 13, 2019 8:19 AM

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Answer 1

babowa

Level 9

78,417 points

Dec 13, 2019 8:46 AM in response to socal59

Is your iMac a 21.5"? That would explain at least some of the slowness as that was a very slow 5400 rpm spinning drive.

Once you've got the internal erased, you could use the internal as a backup disk?

Edit: Just saw you had a T5; make sure you have a current back at all times and read this by CCC developer Bombich regarding those:

https://bombich.com/kb/ccc5/choosing-backup-drive

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Answer 2

socal59 Author

Level 1

20 points

Dec 13, 2019 8:49 AM in response to babowa

babowa wrote:

Is your iMac a 21.5"? That would explain at least some of the slowness as that was a very slow 5400 rpm spinning drive.

Once you've got the internal erased, you could use the internal as a backup disk?

Yea, 21.5. It was fine for most of its life, just this year it slowed way down. Yea I could use it as a back up disk, already use time machine on another drive. But you can never have enough back ups.

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Answer 3

socal59 Author

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20 points

Dec 13, 2019 8:51 AM in response to den.thed

den.thed wrote:

Yes, reformatting it will erase everything including the macOS that is asking for updates.

Plus if you use GUID Partition Map/Mac OS Extended, then you can use it for media storage or Time Machine.

Sounds good. Perhaps run two time machine back ups?

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Answer 4

socal59 Author

Level 1

20 points

Dec 13, 2019 8:59 AM in response to babowa

babowa wrote:

Is your iMac a 21.5"? That would explain at least some of the slowness as that was a very slow 5400 rpm spinning drive.

Once you've got the internal erased, you could use the internal as a backup disk?

Edit: Just saw you had a T5; make sure you have a current back at all times and read this by CCC developer Bombich regarding those:

https://bombich.com/kb/ccc5/choosing-backup-drive

Thanks for the link. It looks like the Samsung T5 is ok to use with Catalina. They did not recommend prior to Catalina, for delayed startups? I've only used it with Catalina, got it a around when Catalina came out.

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