I have a late 2012 27" iMac (13,2) and tonight I tried to update it to Mojave (currently HS 10.13.6). It downloaded just fine, but as soon as I agree to the terms and conditions, it says it cannot verify the drive and that I should start up in recovery mode to run Disk Utility to repair it. So I did that, and Disk Utility right away says the drive is corrupt and cannot be repaired....The machine seems to run just fine....no problem that I can tell at all with it, so this is an unfortunate surprise. I guess I need to know what my options are. I hate to give up on this iMac because it is a BTO machine that I upgraded at the time of purchase with 3.4Ghz quad-core i7, upgraded graphics, and I've also already upgraded the RAM to 32 GB. Internal drive is a stock 1 TB Fusion drive. Is it true that I would have to buy a new display/glass in addition to buying a new SSD drive? Just in order to get inside the machine in the first place? Not to mention paying somebody qualified to do it? This is sounding really expensive or maybe I'm uninformed. Thanks for any and all help.