EDIT 8/21/11: It appeared that this issue may have been fixed in Update 10.7.1, but it reoccured just recently.
Recently after upgrading to Lion, my MBP refuses to allow me to login. I can see the screen and move the pointer, but the password box refuses any entry, and after about ten seconds my pointer turns into the beachball completely freezing up my mac.
I was able to temporarily fix the issue by upgrading my system from 4 to 8 GB of RAM which I already had on order, but after a couple boots, it has returned to it's unusable state.
I have researched some other sites, including the Apple Forums, but I haven't found any great solutions. I'm wondering if anyone else has/had seen this issue, and knows of a good fix that I can utilize until Apple issues an update. (which I will have to install somehow after logging in)
I have a 15 in, 2.4 Ghz i5 MacBook Pro from Spring 2010. I dual boot with Windows 7 under bootcamp and I have a firmware password set. Both instances of the freeze have seemed to occur after coming back to the mac side from W7. I have regular time machine backups.