Had a client run into this situation. Upon logging in to a brand new client install of GP 10, her login would hang during rendering of the Homepage. I tried turning off all the Homepage elements, thinking it was probably Metrics or Outlook making it hang. That didn't help. I even disabled Reminders from the System Preferences menu. That didn't resolve the issue either. And to make the mystery even more mysterious, this issue only happened in one company. She could login to a different company with no issue. Hmmmmm . . .
So, on to Google we went. What I found led me to look at the records in SY01404 (Custom Reminders Setup in DYNAMICS db) and lo and behold - there was a corrupt record in that table for the company the user was having trouble logging into. I cleared that record from the table, and voila . . . login issue corrected.
Living and learning!!