iMac 2012 27.5 inch Desktop is stuck at 100% while booting up.

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Level 1

4 points

iMac 2012 27.5 inch Desktop is stuck at 100% while booting up.

I own a 2012 iMac “21.5 inch” and recently it shut down because it was being slow. When I turned on the Mac, it was loading very slow and it took 30 minutes to reach 100% of the bar. When it reached 100%, it stuck there for hours and hours without end. So I decided to go on YouTube to look for a solution and tried everything from Mac OSX Recovery to resetting the NVRAM or SMC to Safe Mode. And they did not seem to work. Whenever I use Recovery Mode and it took a large chunk of time to let me use Disk Utility and the beachball was preventing me from doing anything. But then when I tried Downloading a new version of MacOS, my startup disk was not there. I couldn’t do anything. Hopefully this is enough information for anyone to help me find a solution to this problem. I have online classes right now, so I haven’t done single thing yet.

iMac 21.5", macOS 10.15

Posted on Apr 20, 2020 1:00 PM

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Answer 1

Kappy

Level 10

362,007 points

Apr 20, 2020 1:23 PM in response to jqoses

Internet/Network Recovery of El Capitan or Later on a Clean Disk

If possible, back up your files before proceeding.

Restart the computer. Immediately, at or before the chime, hold down the (Command-Option-R) keys until a globe appears.
The Utility Menu will appear in from 5-20 minutes. Be patient.
Select Disk Utility and click on the Continue button.
When Disk Utility loads select the target drive (out-dented entry w/type and size) from the side list.
Click on the Erase button in Disk Utility's toolbar. A panel will drop down.
Set the partition scheme to GUID.
Set the Format type to APFS (SSDs, only if installing Mojave or Catalina ) or Mac OS Extended, (Journaled.)
Click on the Apply button, then click on the Done button when it activates.
Quit Disk Utility and return to the Utility Menu.
Select Install OS X and click on the Continue button.

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Answer 2

BDAqua

Level 10

250,259 points

Apr 20, 2020 4:56 PM in response to jqoses

Then I'd get an external drive ^ Install or Restore to that using Time Machine.

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Answer 3

BDAqua

Level 10

250,259 points

Apr 20, 2020 1:22 PM in response to jqoses

See if this works...

Safe Boot from the HD, (holding Shift key down at startup), does the problem occur in Safe Mode?

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Answer 4

BDAqua

Level 10

250,259 points

Apr 20, 2020 3:06 PM in response to jqoses

Sadly that sounds like the drive is dying, do you have a good recent Backup or clone?

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Answer 5

jqoses Author

Level 1

4 points

Apr 20, 2020 2:30 PM in response to Kappy

The problem with the Disk Utility is that it would take a very long time to load in Disk Utility. The beachball is preventing me from doing anything in Disk Utility. And when installing OS X, my startup disk won’t appear.

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