If you work with Outlook 2007 in combination with Exchange, you might get the following error when trying to open a shared calendar:
“The messaging interface has returned an unknown error. If the problem persists, restart outlook“
To open the shared calendar anyway, you have to close and re-open Outlook. It will now work again (for a short while).
Update march 6, 2008: There’s a hotfix available for this messaging interface problem! It’s not a public hotfix yet, but you can request the hotfix. The hotfix includes a solution for the message you get when you try to open a shared calendar in Outlook 2007:
The messaging interface has returned an unknown error. If the problem persists, restart outlook
For more information and to obtain the hotfix, go to
http://support.microsoft.com/default.aspx/kb/941275/en-us
These posts may be related (auto generated):








on Mar 12th, 2008 at 11:08 pm
Hello,
Can you send me the hotfix?
Grtz,
Simon
on Mar 12th, 2008 at 11:36 pm
Dear Simon,
I can’t send you the hotfix, because I’m not allowed to (as far as I know).
You can request the hotfix at the Microsoft site. They responded to me within 24 hours with a link to the hotfix
on Apr 23rd, 2008 at 5:44 pm
I installed office 2007, and I can not see my Inbox e mails… How can I fix this problem?
Best Regards,
on Jul 15th, 2008 at 6:51 am
After installed the Hotfix, the problem still persist.
Any solution?
on Jul 17th, 2008 at 9:32 am
hi howell.tsang. i seem to have the same problem have you received any details on the issue yet.
on Aug 25th, 2008 at 4:27 pm
I’ve been having this issue on one of my users’ work systems, and the solution was to re-create the .pst in outlook (create new user/PST file, then if it works migrate data from the old PST)
Hope this helps!
on Oct 6th, 2008 at 6:36 pm
1. I have Vista/Office 2007/Outlook. I can open Outlook, but cannot open the INBOX. I get the following message: “The messaging interface has returned an unknown error. If problem persists restart Outlook.” Tried this, it doesn’t work.
2. On several occasions I’ve had to open Outlook using SAFE MODE.
Thanks for your help!
on Oct 15th, 2008 at 11:24 am
I have major problems with my Vista/Microsoft Outlook 2007 I get this same error message when I try to empty my Deleted Item folder. I can sometimes delete a few at a time, but the message returns after a few goes. Restarting outlook does not help at all, I’ve tried repairing, uninstalling and reinstalling, and it makes no difference.
on Oct 29th, 2008 at 8:58 pm
I am having similar issue with outlook 2007 . I cannot empty the deleted items folder of junk mail folder..and these folders are not being updated with exchange. I have read that it has something to do with the size of your database being too large.
on Nov 12th, 2008 at 3:58 pm
Has anyone found a solution to the inability to delete emails from the Deleted Items folder in Outlook 2007? I’m not able to delete them and consistently receive error message ‘The messaging interface has returned an unknown error. Restart Outlook’. Restarting Outlook does not solve the problem.
on Nov 13th, 2008 at 8:37 pm
Open the Calendar
Click on File and select Print
Under print select Page Setup and uncheck the option Taks Pad
Click OK and try again
close and reopen outlook
on Jan 22nd, 2009 at 2:13 am
Has anyone come up with a fix to items 9, 10, 11 above?
on Jan 28th, 2009 at 5:38 pm
Thanks for the fix. I had to do this several months ago on another PC but I couldn’t remember the steps. This helped a grreat deal!
on Feb 23rd, 2009 at 3:57 pm
I am getting error message while printing any mails in outlook 2003.
Can someone help me.
Bipin
on Apr 18th, 2009 at 10:28 pm
I had tried sending a video file to too many people through Outlook and the email was sitting in my outbox…. backing up the system. If i tried to move it or delete it I got a message saying “The messaging interface has returned an unknown error. If problem persists restart Outlook.” Restarting Outlook did nothing, emptying my deleted items, did nothing, restarting the PC did nothing.
I followed the advice of Jason HR above – what any of this has to do with my calender function I dont know BUT everything works fine now.
Thanks Jason
Open the Calendar
Click on File and select Print
Under print select Page Setup and uncheck the option Tasks Pad
Click OK and try again
close and reopen outlook
on May 7th, 2009 at 3:17 pm
Hi,
I think my Desktop Sidebar broke it.
I found the following >easy< solution working for me:
Regsvr32.exe %Windir%\System32\Ole32.dll
I found it on en.kioskea.net
I had a problem, I could not use the send email from Office. After this quick registration it worked again.
Office 2007
Outlook 2007