Hello, my 2015 iMac, used by my son, went into this constant restart mode, with the screen grey and wavy(see attached). Zapping PRam doesn't work. I suspect it's the end of life for this computer, but I just wanted to hear a second option.
iMac 27″, macOS 14.5
In addition to den.thed's excellent reply, if you have a spare monitor handy, you can connect it to your Mac to see if you can get a display of your Mac's desktop on it. Even if it reboots, you may still get some information on what may be going on.
Also, have you tried booting up in Recovery Mode or Single User Mode?
Ref:
It is a hardware failure that will cost more to fix than it is worth.
Replace it or repeat and hand-down what you have, then replace yours.
That is an excellent question. It is always best to fully erase and remove the data from drive before recycling.
see > What to do before you sell, give away, trade in, or recycle your Mac - Apple Support
Sadly in this case, you will need to rely on a few less friendly methods.
1) Try and gain access using another Mac in Target Disk Mode. Skip this method if it is constantly restarting.
see > Transfer files between two Mac computers using target disk mode - Apple Support
2) Open it up and remove the internal hard drive yourself. To do that, the following guide will help.
see > https://eshop.macsales.com/installvideos/imac_27in5k_14late_hdd/iMac15-1/
3) Take it to your local Apple Authorized Service Provide and pay then remove the drive.
see > https://getsupport.apple.com/repair-locations?locale=en_US
Sorry, just a follow up question: is it safe to donate it for parts in this state? I do not have anything critical in there, but still, it would be good to know that the privacy is protected. Many thanks again!
Thank you for all these super helpful answers! I tried connecting to an external monitor, and no luck! I will study booting up in Recovery Mode and Single User Mode when I get a chance, and if no luck, I'll follow den.thed's tips on erasing the HD data before recycling.
Thank you for confirming, just as I thought! Well, it served me well for so many years, can't complain...
You're welcome.
iMac - grey, wavy-screen, in constant restart loop
