Outlook doesn’t start

1. Try running scanpst.exe on your Personal Folder. The location of scanpst.exe depends on you version of Outlook and Windows. An overview of the location for you version can be found here.
2. Try renaming outcmd.dat to .old and restart Outlook. All the Toolbars will reset then. This is quite a common problem with Outlook. The default location for this file is:
   C:\Documents and Settings\%username%\Application Data\Microsoft\Outlook
   For more detailed instructions click here.
3. Try running Outlook with the /safe switch via Start-> Run; outlook.exe /safe
   In Windows Vista you can type it directly in the Search field.
   When this works run Help-> Detect and Repair or Help-> Office Diagnostics…
   If loading in Safe Mode fails you can start the Repair operation also by inserting your Office/Outlook CD or via (Add/Remove) Programs in Control Panel.
   After this verify that you have all updates installed via Microsoft Update or Office Update.
4. Still no luck? Start in safe mode again and disable all addins in;
   Tools-> Options-> tab Other-> button Advanced E-mail Options…-> button Add-In Manager…/COM Add-ins…
   In Outlook 2007 you can find this in Tools-> Trust Center-> Addins
   Start Outlook normally and see it works now. If it does enable them one by one until Outlook fails to load again. The add-on you last enabled is most likely the cause of your issue. Check with the vendor for updates or contact them for further troubleshooting their addin.
   Click here if you you get the error that you cannot disable the addin.
5. Try recreating the profile in Control Panel-> Mail-> button Show Profiles…
   For detailed instructions click here