Summary:
Unfortunately, after happily using Ubuntu for many years through many versions on several different machines, and in dual-boot and single-boot configurations, Ubuntu 13.10 on my current laptop freezes so often as to be unusable. After 1-5 hours of unattended operation, the system freezes hard, the display and keyboard become unresponsive, and pings from remote machines report that the Ubuntu box is down, even though it's still powered up. The only thing for it in this state is to hold down the hardware power button to shutdown the machine.
My rough understanding is that the problem is related to Unity and/or the indicator-application-service, but I'm not sure. The issue has been reported pretty widely on the Web, and in several issues on bugs.launchpad.net (for example, https://bugs.launchpad.net/bugs/1228478), but I can't seem to find exactly the right thread in this forum. My apologies in advance if this issue has already been addressed here.
Clarifications:
I'm running an old Toshiba Satellite A205-S4617 laptop with 4 GB RAM and a brand new 1 TB Western Digital hard drive. My old hard drive started throwing input/output errors during the last week, so I figured it was a goner, and I replaced it with the new WD drive. I use this laptop primarily as a NAS/Plex/Squeezebox server in my home, so most of the time it runs unattended. I have a 3 TB Seagate USB drive and two 4 TB Seagate USB drives connected to the machine. I've been using this laptop in this way without any problems since Ubuntu 11.x.
The problems started when I did a kernel upgrade from Ubuntu 13.04 to 13.10. Shortly thereafter, I started to get input/output errors on the hard drive -- reported by dmesg and actively when I tried to access various files on disk -- and the system would freeze overnight. I used gparted to do disk repairs and did a fresh install of Ubuntu 13.10. Eventually I decided that the disk had just died, and did not think that any of the "freeze" issues were related to Ubuntu itself.
I then installed the new hard drive, and did a fresh install of Ubuntu 13.10. No more input/output errors, but the system freezes persisted. Tried again: Did another from-scratch installation of Ubuntu 13.10, but still no joy. Tried adding the "Proposed" packages to my apt sources.list and then doing all the upgrades. Even worse. Tried to boot the machine, but now I just get a mesmerizing flashing of colored horizontal lines as the machine enters the boot loader phase.
Conclusions:
Something in Ubuntu 13.10 is so badly broken that it's become unusable. From what I've been able to find on the Web, I'll try installing KUbuntu instead, and completely bypass Unity and Gnome for now. Don't know if it'll help. If not, I suppose it's on to Debian...
Thanks in advance for any assistance.