The Grand se3 error message

I’m running Cubase 7 on iMac. I made the mistake of trialling the Grand se3 and now I can’t seem to uninstall it. When I try to open sessions that I had loaded the Grand in as a vst instrument, I get a message saying the Grand se 3 will expire soon and then the spinning wheel of death. So I can’t open those sessions.

Sessions where I had not loaded the Grand open fine.

Can anyone help with how I can get rid of the Grand and reopen those sessions? ?