Outlook 2007 is not Starting? Use Scanpst.exe Pro
Most MS Outlook users prefer to update to the latest Outlook version at the earliest opportunity. The most current version always has more features and advanced capabilities than previous versions. Sometimes, however, users decide they prefer the earlier version of Outlook because they are more familiar with how to customize and navigate the older version. Users who have upgraded to Outlook 2007 from Outlook 2003 have reported being unable to open Outlook 2007 after they have downgraded. The inability to open Outlook 2003 is accompanied by an error message stating:
Outlook cannot start because mapi32.dll is corrupt or missing
This is because the mapi32.dll file is upgraded to a newer version when Outlook 2007 is installed. When the program is uninstalled, this DLL file is not removed. When Outlook 2003 is reinstalled, Windows recognizes that the existing mapi32.dll file is a more current version than the one to be installed and chooses to keep the newer version rather than replacing it with an older version.
To resolve this issue, the mapi32.dll file installed by Outlook 2007 must be removed or renamed. The file is located in:
C:\Program Files\Common Files\System\MSMAPI\1033
The user can delete the mapi32.dll file but, most experts recommend renaming the file oldmapi32.dll instead. Now go to the Add or Remove Programs and choose to repair Outlook 2003. During the repair process Windows will not find a mapi32.dll file and will add the Outlook 2003 version. In most cases this will resolve the issue.
Sometimes, users will still have difficulty opening Outlook. This can happen because the Outlook PST file has become damaged during the upgrading and downgrading process. Running scanpst.exe professional will resolve this issue. The Scanpst.exe utility is in the same folder as the DLL file that was just replaced. Run the Scanpst.exe, browse to the PST file and click Scan. The utility will scan the Outlook PST file for damage and repair it. On rare occasion, users will need the assistance of a third party Outlook PST Repair application such as scanpst.exe pro to restore full functionality to Outlook 2007.