When you say you tried starting in safe mode, do you mean you restarted the PC into safe mode and then tried to run Outlook as usual, or that you started the PC as normal then attempted to run Outlook in its own safe mode? If you did the first (i.e. rebooted into into safe mode), try instead booting the PC as normal then typing
outlook.exe /safe
in the Run box at the bottom of the Orb menu and see if that fixes it, then please report back