I don't know if anyone else has noticed this, but the last couple of 4.4 RCs have seen KRunner acting very bad. It frequently locks up, sometimes crashing altogether, other times coming to and continuing to run normally. Calculation results are delayed, app lookups take forever, in general, it seems to have regressed to pre-4.1 peformance. I use KRunner constantly, so this is a problem for me.

Trouble is, I can't pinpoint a cause. There doesn't seem to be a pattern of what causes it to go awry. Sometimes it works without a hitch. Often it does not. This seems to be reflected with the large number of "bug reports" concerning KRunner (particularly in 4.4RC2, though I have noted no improvement since) which give little or no interesting information: "krunner doesn't work consistently recently", "Krunner crashes very often and is unstable", "krunner crash on typing command ", and "KRunner crashes when typing 'dolphin'".

A lot of folks are posting bug reports as though the problems are specific to the app they were trying to launch when they noticed the behavior. But looking over the large number of bug reports related to this issue, I don't think it's specific apps. KRunner is simply acting very flaky.

What concerns me is that the release of 4.4 is not that far off, the number of KRunner reports is increasing, and there doesn't seem to be any major interest from the devs. I'm sure someone is looking into it, but does anyone know who or where?

I use KRunner all the time too (and I've used RCs 2 and 3), and I have not experienced any such issues... I do have KDE built without Semantic Desktop/Nepomuk support, so that might be why - it's supposed to search though all the indexes (just a guess). See if disabling any Nepomuk-related plugins would help.

A few people have suggested it's nepomuk related. I have disabled most of the nepomuk plugins but I left the desktop search as it's very useful; when it works, at least. But since Nepomuk is supposed to be enabled by default in 4.4 IIRC (plus it really is a useful technology), that's not exactly a solution.

Try disabling all the runners the enabling them one by one to see if you can locate the troublesome runner.

Do you have FSRunner enabled? Because i was in your situation until i disabled it. Now strigi is working well so i don't need this runner anymore.

I had huge amounts of problems with krunner in RC2, but in RC3 they have completely gone, so I think we can feel much more confident about krunner in 4.4 release.

I'm still trying out various plugins; I took note of Howl's suggestion particularly; I've had the fsrunner plugin enabled for some time now but never got it to work properly. So I enabled the Nepomuk desktop search plugin (which does work and which I like), maybe Nepomuk isn't to blame after all?

Unfortunately, most of the bug reports on the bugtracker are not going anywhere, probably because there are so many of them without sufficient info.

I'll keep trying to get this narrowed down. I just hope KRunner doesn't ship with bad plugins for 4.4.