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External SSD not showing up at startup

Since updating to Catalina and also shifting to a new SSD external drive (from SanDIsk) on my 2015 iMac, the external SSD drive does not show up on startup. I don't just mean that it doesn't mount. It shows no presence at all (that is, it doesn't show up in Disk Utility even as unmounted).


The work-around is simple. I disconnect the cable connecting the drive to the Mac and plug it back in again. The drive then mounts as normal. And all is good until the next restart.


It's a minor hassle — especially since I don't often restart. But it shouldn't do this. And I have never seen this symptom with any other drive I've used over the years. I have a similar problem with another SanDisk SSD drive connected to my 2020 MacBook Pro.


Is this a known problem with SSD external drives? Is there a known solution? Thanks.

iMac 27″, macOS 10.15

Posted on Jul 24, 2020 5:57 PM

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Question marked as Top-ranking reply

Posted on Jul 24, 2020 6:15 PM

mfiman Said:

"External SSD not showing up at startup: [...]The work-around is simple. I disconnect the cable connecting the drive to the Mac and plug it back in again. The drive then mounts as normal. And all is good until the next restart.[...]"

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Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. hardware), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM. Your hard drive may not be being read promptly, so resetting these, all of the ports would be configured to how they should be..

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1 reply
Question marked as Top-ranking reply

Jul 24, 2020 6:15 PM in response to mfiman

mfiman Said:

"External SSD not showing up at startup: [...]The work-around is simple. I disconnect the cable connecting the drive to the Mac and plug it back in again. The drive then mounts as normal. And all is good until the next restart.[...]"

-------


Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. hardware), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM. Your hard drive may not be being read promptly, so resetting these, all of the ports would be configured to how they should be..

External SSD not showing up at startup

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