Problem waking up from sleep after upgrading to Maverics

My Mac mini have a problem waking up from sleep.

I can see and move the mousepointer but the rest is black.

This problem started after upgrading to Maverics.

I have to restart to get back on track...

I have a 2.3Ghz Core i5 earley 2012 with 8GB RAM and a Samsung Syncmaster 226BW.