iMac won't completely start-up

Question

iMac won't completely start-up

iMac (Retina 4K, 21.5-inch, Late 2015) running macOS 10.13.2. After a recent Microsoft software update and restart, the iMac would not complete the start-up sequence. The white horizontal scroll bar below the Apple logo, comes to a stop at the very end of its path. I've waited 10 or 15 minutes for the scroll to end and the start-up to complete, but no luck. I restarted the iMac (using its internal HD), but the incomplete start-up continues. Doing a start-up from my external back-up drive with a SuperDuper! back-up file works fine.

iMac, macOS Sierra (10.12.5)

Posted on Mar 9, 2018 7:09 AM

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Answer 1

macjack

Level 10

111,216 points

Mar 9, 2018 7:15 AM in response to wallacestuart

Try holding the option key on startup to Startup Manager. Then choose your Mac OS volume and see if that works. If it does there's a problem with the Windows volume.

How to select a different startup disk - Apple Support

If that doesn't work then try an SMC reset:

How to reset the System Management Controller (SMC) on your Mac - Apple Support

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Answer 2

Mar 9, 2018 8:45 AM in response to macjack

'Sorry about screen shot as a reply to your macjack comments. Apple doesn't let postings of original posters to be updated, so I inserted the image the best I could. I tried both of your suggestions, but neither worked to fully start the built-in drive on the iMac. More ideas?

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Answer 3

Mar 9, 2018 10:54 AM in response to macjack

I have the same problem on my 2011 27 in, i7, 3.4 ghz 32 gbs of memory. Stuck on the white screen and I just bought this thing from a supposedly certified refurbished seller. I've combed the web and YouTube and it seems you have to bake your video card. My display is a mess as horizontal and vertical black and white lines going through it right before it crashed. it's not restarting, trying to boot it in Safe Mode Nothing is working, I just get a white screen. Ugh

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Answer 4

Mar 9, 2018 9:51 PM in response to macjack

Yea, wasn't going to go that route lol. I sent it back today hopefully I will get it back sooner rather than later. This is my first Apple product. I hate windows I refuse to use it ever again so hopefully apple and I will work out.

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Answer 5

Mar 10, 2018 1:43 PM in response to wallacestuart

I opted to not start in Recovery Made and reinstall macOS. I'm not acquainted with Recovery Mode and feared trouble with installing a backup on the reinstalled macOS. I did attempt installing my Time Machine backup. I have never done this before. For some reason, Time Machine had 2 options for doing a complete install on the HD. In both cases, Time Machine chose the name of the HD of an iMac that I retired from use about 6 months ago. I skipped using Time Machine. I did restore my month old backup stored on a SuperDuper! partition of my external HD. It worked ... the HD in my iMac did startup completely! I lost more work stored on the iMac's HD than I'd hoped. However, the iMac has restarted successfully for the last few days and I am happy. Thank you macjack for your ideas, but I am now back at work using the backup reinstall that I didn't want to use.

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