iMac won't open from bootable Ext back up drive

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19 points

iMac won't open from bootable Ext back up drive

My iMac (Mid 2011, 3.1 Ghz intel Core i5) won't open when restarting from an external back up drive after changing the start up disk in System Preferences. The screen is black. The mouse cursor arrow is the only item on the black screen. No Apple logo or boot up progress bar is shown. I waited 12 minutes+ and nothing happened.

I depress the power button to shut down. After waiting about a minute, I hit the power button and the iMac starts up as normal. When looking at "About this Mac", it shows that the start up disk is my back up drive. After testing a few apps, everything appeared to be running fine from the back up drive (a partition of a HGST, 2GB SATA drive).

When I reverse the process and return the start up disk to the internal iMac HD, the same thing happens. Have to shut down with the power button etc.

I am running El Capitan 10.11.6. The back up drive is connected to the iMac with the FW 800 port. The back up drive was created with Carbon Copy Cloner 5.0.

I ran both Disk Utility and Disk Warrior on both the internal iMac HD and the external back up drive. There were no major problems with either drive. After running these apps, I tried again with the same result.

Any suggestions? Please help! Not comfortable without a bootable back up drive!

iMac, OS X El Capitan (10.11.6)

Posted on Aug 23, 2018 3:26 PM

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Answer 1

Best reply

Varoop13 Author

Level 1

19 points

Aug 24, 2018 5:20 PM in response to Eric Root

Thanks for your reply, Eric. When the external drive is disconnected, the restart is normal. I did try another port and cable on the external drive with no success.

I did contact support at Bombich Software (Carbon Copy Cloner). They offered some suggestions that I have yet to try. They mentioned resetting the PRAM specifically. I will post the results when I complete this task. For anyone who would like to reset their PRAM or NVRAM, the Apple Support link to do this is below.

Reset NVRAM or PRAM on your Mac - Apple Support

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Answer 2

Varoop13 Author

Level 1

19 points

Aug 29, 2018 4:39 PM in response to Varoop13

After numerous troubleshooting attempts, it appears that the Voyager Q loading dock is the source of the problem. This dock is 8 years old (a lifetime in computer technology) and is no longer supported by Newer Technology (OWC). The firmware on the iMac and the dock are incompatible is the opinion of both Bombich Software (Carbon Copy Cloner) and Newer Technology (OWC) support teams. It's true nothing lasts forever... especially computer peripherals! Hope this post has helped someone with their issue.

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Answer 3

Varoop13 Author

Level 1

19 points

Aug 26, 2018 5:03 PM in response to Eric Root

I reset the PRAM and the first attempt to boot from the BU drive was successful. However, restarting to the original internal HD as the start up disk failed with the black screen etc. mentioned in my first posting. I tried returning the BU drive as the start up disk a 2nd time and it also failed to boot up correctly as it did following the reset.

I was able to boot up from my iMac BU drive on my MBP laptop. Initially, I got the “No Access” symbol, but that was followed by some other options. The one I chose was to run Disk Utility, which did some repairs, one which included something about booting up. I attempted to take a screen shot of the report, but couldn’t since I was still in boot up mode. I should have taken a pic with my phone, but didn’t think of it at the time. I was also able to change the start up disk back to the MBP internal HD without any problems rebooting.

When I tried to boot up to the BU drive on my iMac right afterwards, it did the same black screen etc. procedure. What would cause the BU drive to boot on my laptop, but not my desktop? Both computers are running OS 10.11.6.

FYI, I am using a Voyager Q loading dock from Newer Technology which allows the insertion of raw HD’s into a “toaster like” enclosure. The only difference is using the dock on my laptop, I am using the eSATA connection. I do not have a way to use the same on my iMac. I have tried both a FW 400 and a FW 800 connection to the iMac. The USB on my iMac is 2.0 so I didn't try it because of the slow speed.

I would appreciate any suggestions anyone can offer. All the troubleshooting has been very time consuming, and I am frustrated over not being able to find a solution. I have also contacted Bombich Software today (Carbon Copy Cloner) with the same information. I will post any future updates on this issue. Thanks.

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