Hi there,
My problem is that the krunner applet(?) appears after several seconds (15 -20 seconds) after I press alt+f2 or "click right >> Run command" or simply command
# krunner
in a console.
It didn't happen as so in the previous version of kde.

What can be wrong? It's very annoying .

things to try:

1) test as a new/different user

2) rename your Krunner rc file ~/.kde/share/config/krunnerrc or ~/.kde4/share/config/krunnerrc, there is an app folder also, mine is empty, but if yours is populated then rename it also ~/.kde/share/apps/krunner or ~/.kde4/share/apps/krunner.

3) empty your cache and temp folders /var/tmp/kdecache-user_name and /tmp/kde-user_name

4) Running kbuildsycoca4 --noincremental may also help

Hi google01103,
Thank you very much for your prompt replay!
I did:
# kbuildsycoca4 --noincremental

and know things came back to normal.
Thank you again!