Mac OS booting from wrong start up disk

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Level 1

4 points

Mac OS booting from wrong start up disk

I have a 2014 iMac whose internal SSD startup disk broke down. I installed a colostomy bag of a SSD to run the OS as a startup disk and everything has been peachy for months.

Well, yesterday I guess the original SSD has started to work, and now it won't NOT boot up from that original startup disk.

I've tried booting up in recovery mode and choosing the external as a startup disk, setting it as the default startup in system preferences- nothing seems to work. Nothing seems to be wrong with the external drive, it just won't choose it now that the original one has decided to work.

I have some stuff on my desktop from the more recent that I'd like to get, but it doesn't look like I can access it unless i'm logged in.

What to do?!

iMac 27″, macOS 10.15

Posted on Jan 15, 2021 10:08 AM

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Answer 1

Best reply

tbirdvet

Level 6

13,893 points

Jan 15, 2021 4:34 PM in response to mjohnson1234

The way the system works is that if the drive you pick will not start for some reason the system looks for another. In your case it cannot start from your external even if set it that way so it sees the internal and starts from that drive. I would check the external drive for errors (use first aid) and also check the connection (cable).

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Answer 2

PRP_53

Level 10

86,815 points

Jan 16, 2021 2:31 AM in response to mjohnson1234

Have seen this before on others with similar issue. They have reported the solution required Re-Partitioning the Offending drive and format as required of versions of macOS and do a clean install to that drive. In this case, the internal drive is a bit too unreliable to consider using as Main Bootable Drive. Ssd that suddenly stop working and start working . . . arrive at own conclusions.

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Mac OS booting from wrong start up disk

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