I too had this issue, and it had nothing to do with recreating profiles or going into the registry.
I’ve had this happen to me all too often, had 3 different solution options that I was trying, and found one that works every time (so far). The issue for me is with Shortel Call Manager and the “Agent.exe” process.
For those who use the Shortel contact or voicemail integration, it can sometimes break Outlook if you close it. When you try to re-open Outlook, it can hang on loading profiles until you reboot or kill off the "agent.exe" process. Of course uninstalling
voicemail integration solves this problem, but most of us like that feature (listening to voicemail from an email message).
In short, kill the Agent.exe process if you get stuck. If you want to try a more permanent solution you could try modifying the Agent.exe process to run in XP compatibility mode, but no guarantee.
There are other programs that use Agent.exe (Macromedia, Roxio, etc.) and this solution may work for that scenario as well.