Microsoft Outlook 2010 Command Line Switches

When troubleshooting issues with Microsoft Outlook 2010, utilizing the command line start-up switches can be quite beneficial.

XP:
Start
Run
"c:\program files\microsoft office\office14\outlook.exe" /nopreview

Vista and Win 7:
Start
All Programs
Accessories
Run
"c:\program files\microsoft office\office14\outlook.exe" /nopreview

/nopreview - starts outlook with preview reading pane disabled
/safe - starts outlook in safe mode
/cleanautocompletecache - clears the names and email addresses from the autocomplete cache


Source and a boat load more switches: Microsoft Outlook 2010 Help and How-To Article