It looks like the installation of Groupwise 'told' Outlook to use an 'information service' from gwmsp1.dll (the gw obviously stands for Groupwise). And the uninstall didn't inform Outlook to go back to it's previous settings. Uninstalls tend to be incomplete.
It's quite possible that the information in the registry regarding this 'service' isn't touched by the uninstall of Outlook, being added later. So it happily pops up again after the reinstall. That's how things work.
Things to try:
1. You can configure Services in Outlook. So try to remove the groupwise service. If Groupwise didn't actually update or erase the standard services this might work.
2. If it doesn't work immediately: uninstall, run the appropiate Office eraser from Microsoft (see below) and reinstall.
3. If that doesn't help: uninstall, run the Office eraser, and delve into the registry with regedit to manually erase all traces linking Outlook to Groupwise. Be careful, and now how to backtrack in your OS (Win 98: scanreg /restore; XP: System Restore). Then reinstall.
Instructions and downloads for Office eraser can be found at:
If you happen to have Windows XP and were wise enough to set a System Restore point before installing Groupwise, you might be able to go back in time without all these troubles.
Hope this helps.
My school had us all install the new version of Groupwise on our computers. However, they failed to tell us that Outlook & Groupwise don't co-exist very well together. When I tried to open up Outlook, I got an error message: "Unable to open default email folders. An unexpected error has occurred. MAPI was unable to load the information service from gwmsp1.dll. Be sure the service is correctly installed and configured."
The tech came over to help and basically replaced my earthlink account info with my school email account info. I un-installed the Groupwise program, but continued to get the same error message.
This morning another tech person from my program suggested re-installing Office, which I did. now, when I try to open it, I get the same error message as above. When I click OK, I get a box that asks "Would you like to open your default File System folders instead?"
When i click "yes" to this, and go to click on my inbox, i get the same aforementioned error message.
Does anyone have suggestions? I would like to go back to my old settings...i can access Groupwise from my school's website. I am pretty bummed because all my contacts, calendar, and messages in my inbox seem to be gone.
Any help or suggestions you have would be appreciated.