FIX: "MAPI was unable to load the information service Pstprx.dll" error message when you upgrade to Office XP

If you upgrade to Microsoft Office XP while you are using Microsoft Outlook 2000 in Internet Mail Only (IMO) mode and you remove Office XP, revert to Microsoft Office 2000, and upgrade again to Office XP, you may receive the following error message when you start Outlook 2002: NOTE: The file name in the error message that you receive depends on your type of upgrade. If you upgrade over Outlook 2000 in Corporate or Workgroup (CW) mode, the filename is Pstprx.dll. If you upgrade over Outlook 2000 in IMO mode, the filename is Pstprx32.dll.

This problem can occur because Outlook 2002 upgraded the profile once and set a registry key that specifies not to upgrade the profile again. When you revert to Outlook 2000 IMO, choose to use the current profile, and upgrade to Outlook 2002 again, that profile is skipped during the upgrade process.

To resolve this problem, obtain the latest service pack for Microsoft Office XP.

To work around this behavior, use the following methods.

Method 1: Change Profiles

To do this:

1. Close Outlook 2002.
2. Click Start, point to Settings, and then click Control Panel.
3. Double-click Mail.
4. Click Show Profiles.
5. In the box that reads The following profiles are setup on this computer, verify if there are two profiles listed. If there are two profiles listed and Outlook is configured to use a profile named Microsoft Outlook Internet Settings, the profile may be damaged. Configure Outlook to use the second profile. To do this:
   1. Click Always use this profile, and then in the box below this selection, click on the second profile listing.
   2. Click OK.

Method 2: Manually Create a Profile for Outlook 2002

To do this:

1. Close Outlook 2002.
2. Click Start, point to Settings, and then click Control Panel.
3. Double-click Mail.
4. Click Show Profiles, click Add, name the profile, and then click OK.
5. Click Add a new e-mail account, and then click Next.
6. Click a type of account, and then click Next.
7. In the E-mail Accounts dialog box, enter the necessary information, and then click Next.
8. Click Finish.
9. If the Always use this profile option is selected, select the profile that you just created, and then click OK.
   
   NOTE: In some cases you may need to click the Prompt for Profile option to correct this problem after you create a new profile.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
This problem was first corrected in Office XP Service Pack 1.