I recently upgraded a machine to Ubuntu 10.04, which has been an overall positive experience. But, the one bad thing was that I could no longer launch links from my emails or RSS feeds (using Thunderbird and RSSOwl, respectively).
In searching for the answer, I used
to try to see what was going on. I found that somehow, something was trying to launch firefox-3.5, which no longer exists (3.5 having taken over as the default version now). Nothing in /etc/ was referring to this… Some searching on the web led me to learn about xdg-open, which calls gnome-open, which uses settings in GConf to figure out how to launch a URL. Launching gconf-editor and finding ‘/desktop/gnome/url-handlers/http’ and ‘/desktop/gnome/url-handlers/https’, I saw that the command for each was ‘firefox-3.5’. Changed those back to ‘firefox’ and everything was cool again.
Now that I see that, I think I used gconf-editor to set those the other way when I first started using firefox-3.5. So it’s sorta my fault, although it wouldn’t be a terrible thing if the install scripts looked for and repaired that sort of error.