Not sure if this is a KDE problem or a problem with the Kubuntu packages. I've been running QtCreator 1.2 for a long time never having a crash, I recently upgraded to QtCreator 1.3 and was using that for a few weeks also without any crashes. This was all in Kubuntu 9.10 and KDE SC 4.3. When the 4.4 beta packages were released, I installed those and now both QtCreator 1.2 and 1.3 crash frequently. This problem remains after upgrading to Beta 2.

It seems like the crash almost always happens when I'm pressing "." to call a member function, so I think it may be related to the autocompletion list. I've also noticed that once the crash happens, it suddenly happens much more frequently (sometimes immediately upon opening a project) until I restart my desktop.

I find this a little odd because QtCreator isn't a KDE application, it's pure Qt, but this bug definitely seems related to KDE, not QtCreator or Qt, since I used both QtCreator 1.2 and 1.3 with Qt 4.5 and 4.6 without any problems, only after updating to KDE SC 4.4 did this problem start, and once the problem started, it's present with any version of Qt or QtCreator that I try.

Qt creator likely loads KDE plugins, which may have become incompatible in some way. If you install from packages, please ensure they are up to date.

If you install from source please ensure they are all compiled aganist the same revision of Qt and KDE Libs.