First login after boot takes forever after installation of Remote Administration (VNC)

I’m running Leap 42.1, x86_64, KDE 5.4.3, QT 5.5.1.
I recently installed Remote Administration (VNC) in an (unsuccessful) attempt to fix a problem with drag and drop.
Ever since, after I boot and enter my password, the following happens: The SuSE logo (chameleon) and the light bulb appear, then the screen becomes black and a short moment later I see a mouse pointer, which I can also move. Then, after at least 10s, the KDE desktop appears and everything is ok. It often takes longer than 10s. This morning I reset the computer after about a minute.
I deactivated Remote Administration, but that didn’t change the login behavior. If I log off and then log in again, it’s as fast as it always was.
Any hints?

Thanks, Stephan

I don’t know what happened, but the last three times I booted and logged in, I didn’t have this problem anymore. Consider it closed.