If you are getting following error message while doing some activity within Outlook 2003, it could have been caused by Google Desktop –
The messaging interface has returned an unknown error. If the problem persists, restart Outlook.
I was getting this error while trying to access my Address Book. Whenever I used to hit To/CC/BCC buttons while composing new message, I got this error message. Or when I tried to open Address Book by going to Tools -> Address Book. Or when I just hit Ctrl + K.
If you also get this problem, go to Tools -> Options -> Other -> Advanced Options.
- First click on Add-In Manager button and uncheck Google Desktop Search Outlook Addin. Click OK.
- Then click on COM Add-Ins button and uncheck Google Desktop Outlook Toolbar. Click OK.
Restart Outlook and the problem is gone.
One alternative is to start Outlook in Safe Mode by typing Outlook /safe in Windows run command box.
If you are thinking about uninstalling Google Desktop and re-installing it, I already did that but it doesn’t help at all. So it doesn’t matter if you installed Microsoft Office 2003 first or the Google Desktop 5.1 first…you are going to end with the conflict between the two.