When I upgraded to Ubuntu 9.10 Karmic from 9.04 Jaunty, it appeared that the upgrade process preserved all my settings. However, I’ve found several that were changed for unknown reasons.
First, I found that my screen kept blanking after about 5 minutes of idle time. So, I sent into System -> Preferences -> Power Management. I worked my way through all the settings numerous times, but they didn’t make any difference in this behavior. Hmmm.
After a while of this nonsense, I remembered one other possibility. I went to System -> Preferences -> Screensaver:
I had alway used the screensaver to put up a blank screen after 1 hour. The Karmic upgrade set the timer to 5 minutes! I have no idea why Karmic changed that setting, but it’s fixed now.
Also, I had networked my printers through my desktop for the laptop to use. This all worked swimmingly in Jaunty. It stopped working after the upgrade to Karmic. I checked the printer properties under System -> Administration -> Printing and sure enough, Karmic had “unshared” them. So, I right-clicked on the appropriate printers and rechecked Shared:
But that didn’t fix the issue. Digging further in the Printers dialog menu, I clicked on Server -> Settings in the upper left. Sure enough, Karmic had reset the server not to share any printers on my network. So, I checked the “Publish shared printers connected to this system” box which Karmic’s upgrade had cleared:
After that, all worked fine.
It’s hard to understand why Karmic changed these particular settings, but the changes caught me off guard. Hopefully this will save someone else some time.