Unity 4 startup problems

Hi,

I've downloaded and installed unity 4 (was using unity3.5). For some reason, first time I open up unity for any given day it now gives me an error about license. I re-choose which license, free at moment. Did try trial at first, but due to message each time I dropped down to free one. If I then close unity I can re-open usually okay, for that same day. It's getting a bit anoying to say the least and I am also concerned if each registration gets logged and I may be reaching a limit.

I'm using a windows 8 machine, just upgraded but was also happening on windows 7 (same machine).

Any suggestions / help?