Old iMac won't boot all the way

At best Disk Utility is a poor tool, more often than not it misses problems. You need professional tools however you don't have them so your best bet is an Apple Authorized Service Provider (mentioned below). My experience tells me if the computer is 5 years old or older and has the original (or a 5 + year old HD installed) chances are very high the HD is dead. In that case replace the HD.

Apple is 100% correct on their assessment and you should follow the steps. If you don't want to then perhaps you can find an independent Apple Authorized Service Provider that will work on it. If you don't know of any independent AASP's in your area please click Apple Authorized Service Provider Locator (AASP) & Genius Appointment to locate one. Depending on its age though it may simply be telling you it is ready for recycling and should be replaced.

Good luck though.

Sure, pritcharddesign, I'd be glad to help you, if you can help me (and us)

on the foot of your iMac, there should be a model number, it starts with "A" then 4 numbers/digits. Jot down that model number and cross-reference it at everymac.com, there should be a way to search there by model number, or just browse through the iMac section until you find one that matches your model number, and there you go, it'll have the year, and all of its specs, I don't know if it'll tell you what the latest version of the Mac OS you can install on that iMac, but you can find out by going here for downloading the various versions of the Mac OS, and seeing what their requirements are: How to download and install macOS - Apple Support (CA)...Sad to say, I don't see Mavericks listed, officially, eg in the App Store, which is a shame, as I thought it was one of the better versions of the Mac OS, much better than Yosemite, which had a major bug in it: The Wi-Fi didn't work at all if you installed Yosemite, period...there might be a way to get Mavericks, but you'd have to see the link, and decide for your self...

https://archive.org/details/os-x-mavericks-installer-app...if you were to try to install it, which I'm not saying is good or bad, you'd have to maybe make a Mac OS X Bootable USB stick/flash drive/thumb drive.... for that you'd need a Mac OS X Bootable drive making application, such as DiskMaker X, there may be others out that that work, too,

and you'd have to find some way to turn your Mac OS system's clock back to Feb 14, 2016 beforehand... I'm probably going to get in trouble for posting the second part, but usually it goes something like this....figure out the year of your iMac, then look up the requirements for each version of Mac OS listed in the first link, then pick one that comes closest to the specs and year of your iMac.....then use a USB stick of 8 to 16 GB Capacity (size), Mac formatted, plus the appropriate installer, and the Mac OS X Bootable drive making application, plug the Mac formatted USB stick into a Mac, run the Mac OS X Bootable drive making application, point it to the installer, which should be on the same drive as the Mac OS X Bootable drive making application, and let it work its magic, when it says "Done", safely eject the USB stick from that Mac, and then unplug/disconnect it from that Mac, turn around and face the mac onto which you want to install a copy of Mac OS X from a USB stick. On that Mac, do a reset smc/PMU followed by 3-4 pram zaps, as per this link: https://www.macworld.com/article/224955/how-to-reset-a-macs-nvram-pram-and-smc.html, after the last one, hold down the "Option" key as it's starting up/booting up to get to the Startup Manager, Plug in the Bootable USB stick/thumb drive/flash drive....you should see a screen with all potentially bootable drives on it, including, if you have a CD/DVD drive, and you have a Mac OS X bootable DVD in the drive, a bootable Mac DVD....left and right to pick one, then mouse click/Enter-Return on your keyboard to select it, and confirm it....then let it do its thing..... the last thing is to make sure that you have said that you want your internal drive/storage to be the Startup/Boot drive....at the end, as this is not done by default (automatically) , you have to say that you want to do that, otherwise, it'll just boot/Startup from the USB stick only.... when you have successfully reinstalled the Mac OS of your choice onto your old iMac, and it boots up /starts up OK, then the uSB stick should show up, click on it once, and then choose "Eject" and safely eject it...once it tells you it's OK to disconnect/unplug your USB stick from your Mac....

WHEW !!!

John B

I had this with an old Macbook a few years ago and put Linux on it and used it as a video file server for a while until the battery swelled up, at which point I binned it. There are a lot of Linux distros out there - I haven't kept up, but GIYF. I'm not an IT expert by any means, but I had no difficulties at all. You'd obviously have to make sure that drivers are available for your scanner before starting.

Good luck.

If your Mac starts up to a question mark