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My iMac 27 in won't start up. When I hold the off/on button, the apple shows and the sound but then the screen goes black

After the screen goes black, I press the on/off button and hold it for awhile and let go. After a few seconds, I push and hold it again until the apple and sound and then it goes black again.

iMac 27″ 5K, macOS 13.3

Posted on Aug 12, 2023 11:28 AM

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Question marked as Top-ranking reply

Posted on Aug 12, 2023 1:22 PM

Hi Puterwade,


If I understand correctly, your 27" iMac shows the Apple logo and plays the startup chime when you press the power button, and then the screen immediately goes black but the Mac remains powered on?


If that's correct, you might want to try starting up from macOS Recovery to see if it's a software or firmware problem. Fully power off your iMac, connect a wired keyboard, then power on your iMac while holding down Command-R. Release the keys when the Apple logo and a progress bar appear.


If you're using a Windows keyboard, try holding down Windows-R or Alt-R as you power on the iMac.


Please let me know whether the issue still persists when trying to access macOS Recovery, or if you can boot into Recovery without issues.

5 replies
Question marked as Top-ranking reply

Aug 12, 2023 1:22 PM in response to Puterwade

Hi Puterwade,


If I understand correctly, your 27" iMac shows the Apple logo and plays the startup chime when you press the power button, and then the screen immediately goes black but the Mac remains powered on?


If that's correct, you might want to try starting up from macOS Recovery to see if it's a software or firmware problem. Fully power off your iMac, connect a wired keyboard, then power on your iMac while holding down Command-R. Release the keys when the Apple logo and a progress bar appear.


If you're using a Windows keyboard, try holding down Windows-R or Alt-R as you power on the iMac.


Please let me know whether the issue still persists when trying to access macOS Recovery, or if you can boot into Recovery without issues.

Aug 14, 2023 6:10 AM in response to Encryptor5000

I bought a new wired keyboard for a Mac. When I press the power button on the iMac 27, it may start the apple logo and chime, but no progress bar. It will show for maybe 15 seconds and then appears to restart with same apple logo and chime, and no progress bar. It keeps doing that for hours. If I press the power button it will shut off and maybe never restart.

Aug 19, 2023 10:35 PM in response to Puterwade

Good to know! Can you please try holding down Option-Command-R instead at startup? This forces Internet Recovery, and should show a spinning globe instead of the Apple logo and progress bar.


If a spinning globe still doesn't appear and the previous symptoms persist, it could be a possible firmware issue. If your Mac has the T2 Security Chip, you could try reviving the firmware: Revive or restore an Intel-based Mac using Apple Configurator - Apple Support (CA)


If your Mac doesn't have the T2 Security Chip or if the revive doesn't resolve the issue, you could also try resetting NVRAM or the System Management Controller (SMC):


Reset NVRAM on your Mac - Apple Support (CA)

Reset the SMC of your Mac - Apple Support

My iMac 27 in won't start up. When I hold the off/on button, the apple shows and the sound but then the screen goes black

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