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Slow Boot Up on Mojave - External USB SSD

Loner T hope you are out there. I just upgraded my iMac to Mojave and now the system is booting extremely slow. I have my Mac OS on an external USB SSD drive and my data files on the internal 1 TB drive. The system was working perfect until recently. I did a backup and then wiped the drive completely and reinstalled Mojave and it is still having issues. Not sure where to start. The system does appear to function fine once booted up and logged in. I was planning on running Bootcamp the iMac but with all of the issues I decided to keep running Fusion.

Thanks!

iMac (27-inch, Late 2013), OS X El Capitan (10.11.3)

Posted on Oct 4, 2018 5:04 PM

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Dick Richards Author

Level 1

8 points

Posted on Oct 5, 2018 4:39 AM

Basically I have an iMac 27" and boot/run off of an external USB SSD and have my data on my data drive that is internal. Everything was working fine and the system rebooted completely normal. I upgraded to Mojave and things seemed to be working but I actually never rebooted after the upgrade so I didn't see the error until my keyboard had a malfunction where the Shift key kept transmitting so I had to buy a new keyboard. Once I got the new keyboard the boot continued to hang. I originally thought it was a Safe Mode issue because of the Shift so I wiped the whole drive but the Mac is still hanging at boot. I think it takes around 1.5 mins or a little less for the Apple icon to finally appear.

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35 replies

Loner T

Level 9

59,513 points

Oct 5, 2018 1:14 PM in response to Dick Richards

In System Report, can you check the link speed available from the external disk?

Oct 5, 2018 2:22 PM in response to Loner T

How do I do that?

Loner T

Level 9

59,513 points

Oct 5, 2018 2:36 PM in response to Dick Richards

About This Mac -> System Report -> USB.

Loner T

Level 9

59,513 points

Oct 6, 2018 7:30 AM in response to Dick Richards

Is the external SSD self-powered or powered by the iMac?

Oct 6, 2018 12:49 PM in response to Loner T

Loner T

Level 9

59,513 points

Oct 6, 2018 1:17 PM in response to Dick Richards

If it is connected to a USBc port, there are some known power timing issues. Normal USB2/USB3 ports should continue to work. Is there an indication on the external SSD of the power state?