Comment 5 for bug 1631058

I have this problem as well. Was already running 16.10 Development branch successfully, I think that when 16.10 was released that the next sudo apt update / upgrade changed something. I started getting errors that updates needed to be applied, but some lock file was read-only; then whole screen dimmed and keyboard and mouse was unable to do anything (I could still move mouse pointer around screen but unable to click anything). After 15 minutes I noticed that the time display was frozen (15 mins late) and attempted a reboot. I was running KDE Plasma Desktop. But I also had gnome installed. Now I am unable to boot into the sign in screen. Boot process freezing during initialization of Ubuntu 1st error I get is:
[ 2.859598] SCSI host8: runtime PM trying to activate child device host8 but parent (12-1:1.0) is not active
[ 36.308445] ata8.00: exception Emask 0x52 SAct 0x0 SErr 0xffffffff action 0xe frozen

Sorry, I can't transcribe any more manually, but rest of messages are ata8.00 and ata7.00 errors.

Final line before computer gives up is:
[ 36.450198] ata7.00: status: { DRDY }

Then it is stuck on the blinking cursor.

Tried to reboot into recovery, same thing happened.

Once it is stuck, I have to push reset button, or power PC off completely.
Upon reboot, same thing happened, except when I used UEFI to boot from another disk, but that's FreeBSD ZFS Boot, that I am no longer use (don't have password for any more).

At this point I'm not sure what could possibly recover my data from the Ubuntu partition.