RE: Frozen Debian testing upgrade

[6477417.633822] systemd-logind[8642]: Failed to fully start up daemon: Input/output error

Partway through this upgrade I lost the ability to click anything with the mouse, can still run it around the screen and it wakes up the screen saver but can't click > anything.

Have you checked out the obvious things like that you might have a failed disk? 'dmesg' or /var/log/kern.log should show some errors if this is the case. Also use smartctl to check the health of the disk and run a self test. James