In safe mode, disable all your add-ins and restart Outlook (in 'normal'
mode). If that works OK, enable some add-ins and try again. Through a
process of trial and error you should be able to work out which add-in is the
likely culprit.
If, however, you disable the add-ins and still get the same problem after a
restart, try running with each of the following switches:
/safe:1
/safe:2
/safe:4
/safe:1 switches the reading pane off. If that works fine but the others
don't then it sounds like there's a problem displaying the active mail in the
reading pane. You could try moving the 'active' mail to another folder to
make a different mail the active one when Outlook starts - perhaps there's
something in the HTML of that mail Outlook chokes on. If it happens
regardless of which mail, I have to confess I don't know what do do with
that. I haven't seen a problem like that before and I don't know any fixes,
but at least we've narrowed it down that maybe someone else can help you.
/safe:2 starts Outlook without checking for mail at startup. If this one
works fine but the others don't, try creating a brand new mail profile and
loading Outlook with that.
/safe:4 ignores your outcmd.dat and *.fav file. If this works and the
others don't, look in %userprofile%\Application Data\Microsoft\Outlook for
outcmd.dat and *.fav. With Outlook closed, rename those files and restart
Outlook.
Sorry for information overload, but trying to cover as many avenues as
possible...
