Seems I'm having the same problem folks have had in the past. I've tried entering my registration info both via the MyEclipse menu and through the Preferences dialog, but either way, every time I restart Eclipse and choose that workspace, it tells me my registration has expired every time.

The user.home directory setting is valid and myeclipse.properties exists there, but it doesn't seem to be getting updated. I have fixed the problem by manually entering my registration information into myeclipse.properties, and it seems to be retaining it now, but wanted to notify you, as there's obviously a bug in there somewhere.

Seems to be the same problem with older versions folks were having in these threads:
http://myeclipseide.com/PNphpBB2-viewtopic-t-6395-highlight-registration.html
http://myeclipseide.com/PNphpBB2-viewtopic-t-8747-highlight-registration.html

Are you using multiple workspace like one of the threads suggested? Can you go to MyEclipse > Installation Summary > Installation Details and paste the information here for me. I would like to try reproducing this at my end as well.

Thanks.