Something happened on my HTC Tattoo (V1.6) this week that caused lots of apps to crash on start-up. I think it may have been due to their settings getting corrupted somehow, but I don't know what caused that.
I've been able to get some working again by uninstalling them and then installing them again. Obviously I lost any set-up by doing this.
Is it possible to reset the settings for a given app? I don't even know where they are stored. Is it in an .xxx type file as on Linux? It would be useful to know where they are so I can back them up in future.
Update August 2011: Now it's happening again. Google apps failed first, but then Facebook and last.fm stopped working. Tried clearing data/cache with no improvement. Can't re-install some apps as they are no longer available for 1.6. I do intend to try upgrading when I get time.