Earlier this week my late-2014 iMac started showing odd behavior: the WiFi wouldn't turn on and when I tried to access System Preferences by clicking the Apple logo, I wouldn't get a drop down. My Time Machine is on a NAS and size-wise and timestamp-wise seems okay.
I tried reboots and reset NVRAM to no avail. Eventually booted into recovery and Disk Utility showed my Fusion Drive as disk0s2 (HDD) and disk1s2 (SSD) and disk2 as OS X Base System. Both the Fusion Drive disks were red but warned that a "fix" would erase them both. Time Machine or not, I clicked cancel (my fatal mistake?).
I went to re-install the OS and after a long time, a dialog appeared saying "macOS could not be installed on your computer. Reboot and run diagnostics." When I did that, diagnostics came back clean ("Reference code ADP000").
So I rebooted and now I no longer get the "macOS Utilities." If I boot into recovery or Internet recovery, it just goes straight to install the OS, which eventually fails as above.
I burned a Catalina boot USB but that has the same behavior (I can only install, not inspect / erase / repartition the disks, and the install fails after a lengthy period).
I've also tried booting from a Linux USB and that semi-fails, saying "Unable to find a medium containing a live file system" and looping with a mmc0: error. I can get a limited command line with a number of "Built-in commands" but I don't know enough to spelunk further using those.
tl;dr: my iMac won't boot except to "Install OS X," which fails, but then the diagnostics are clean. Is there anything I can do?
I tried reboots and reset NVRAM to no avail. Eventually booted into recovery and Disk Utility showed my Fusion Drive as disk0s2 (HDD) and disk1s2 (SSD) and disk2 as OS X Base System. Both the Fusion Drive disks were red but warned that a "fix" would erase them both. Time Machine or not, I clicked cancel (my fatal mistake?).
I went to re-install the OS and after a long time, a dialog appeared saying "macOS could not be installed on your computer. Reboot and run diagnostics." When I did that, diagnostics came back clean ("Reference code ADP000").
So I rebooted and now I no longer get the "macOS Utilities." If I boot into recovery or Internet recovery, it just goes straight to install the OS, which eventually fails as above.
I burned a Catalina boot USB but that has the same behavior (I can only install, not inspect / erase / repartition the disks, and the install fails after a lengthy period).
I've also tried booting from a Linux USB and that semi-fails, saying "Unable to find a medium containing a live file system" and looping with a mmc0: error. I can get a limited command line with a number of "Built-in commands" but I don't know enough to spelunk further using those.
tl;dr: my iMac won't boot except to "Install OS X," which fails, but then the diagnostics are clean. Is there anything I can do?