The messaging interface has returned an unknown error. If the problem persists, restart outlook” in Outlook 2007

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

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Can you send me the hotfix?




I installed office 2007, and I can not see my Inbox e mails… How can I fix this problem?
Best Regards,


After installed the Hotfix, the problem still persist.
Any solution?


hi howell.tsang. i seem to have the same problem have you received any details on the issue yet.


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!


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!


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.


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.


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.

Jason HR

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

Michael McCabe

Has anyone come up with a fix to items 9, 10, 11 above?

Matt Romero

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!


I am getting error message while printing any mails in outlook 2003.

Can someone help me.



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… Read more »


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

I had a problem, I could not use the send email from Office. After this quick registration it worked again.

Office 2007
Outlook 2007


grrrr I have just installed microsoft outlook 2007 and when i click to go into my inbox i get the same error… i’ve tried the suggestions above but i can’t find the tasks pad thingy and I have no idea how to fix it. Please HELP. thanks


hi, i have same issue with Rina.
i have looked for tasks pad but i can’t find this tasks pad in outlook 2007.

i still couldn’t see my inbox. all my works are in there. what should i do.
anyone, please??


I have gotten the same messaging trying to send/receive emails or deleting emails. It appears that it is trying to download emails, but then I get error messages. I’ve tried the few solutions listed above, but nothing helps. (There are envelope icons on the toolbar at the bottom of the page that appear to be loading. THey are identified as Symantec Email Scanner.)
Any other suggestions.


There is a program in the Microsoft Outlook folder that may work that’s called scanpst.exe. It’s located C:\Program Files\Microsoft Office\Office12. It’s a scan repair utillity that worked for me.

I tried all the solutions listed above to no avail.

Good Luck


Hi All, I am running Office 2007, Exchange 2007, Windows XPSP3. There are 2 specific issues I have found that cause the error ““The messaging interface has returned an unknown error. If problem persists restart Outlook.”: 1) If I have a word or excel file in the old version (.doc or .xls) open and attempt to use the “Attach to Email” button, when I click send I get the error 2) Occasionally when one of my colleagues attempts to access another person’s calendar, she receives the error (I did what Jason HR said to no avail). The only way she… Read more »


I am unable to open my sent items to view the mails I have sent out. Please help.


I had the same problem, scanpst.exe repaired my .ost file and fixed my problem.

Dean Williams

I Had this issue with a 97 – 2003 pst file I could not move or delete the e-mails within it. In the end I created a new PST file and copied the folders one by one by right clicking on the folder and clicking copy and then selecting the new PST archive 🙂


“The messaging interface has returned an unknown error. If the problem persists, restart outlook


I have the same problem — well, at least the same error message. Message comes up when trying to open certain e-mail messages and also when trying to create a new e-mail message. Problem appeared in Outlook 2003. Could not resolve it, so finially I decided to just go back to Outlook XP. Same problem in Outlook XP. I have even gone so far as to totally uninstall every Microsoft Office product then re-install everytihng. No joy. Please remind me why we put up with the crapware Microsoft sells us? Oh yea — Exchange server requires Outlook to utilize all… Read more »


thanks to all…my problem solved


i also got this error, was unable to send any mails, this error kept popping up. Searched on net, looked like there are quite a few different reasons for this mesg.

Found a solution that worked for my case: went to tool -> trust center -> email security and switched off “add dig sign to outgoing msgs” since i don’t need digital signs. voila! it worked, the msg disappeared forever.

ps – sometimes outlook automatically switched the option on when restarting. but just switching it off makes everything ok.

Outlook 2007 PST Repair

In order to deal with pst related issues you can try outlook inbox repair tool i.e. scanpst.exe but in case if it fails to resolve your problem then ultimately you will have to take help of third party Outlook 2007 pst repair tool if you are using Outlook 2007 version.


San PST utility is an inbuilt application that is used to repair corrupted PST file


Hi! I just wanted to ask if you ever have any issues with
hackers? My last blog (wordpress) was hacked and I ended up losing months of hard work due to no back up.
Do you have any methods to protect against hackers?

Health Plan

I hink everything said made a lot off sense. However, what about this? suppose you addedd a little content? I aam not suggesting your information iis not solid., however suppose you added a post title that makes people desire more? I mean The messaging interface has returned an unknown error. If the problem persists, restart outlook” in Outlook 2007 – ITExperience.NET is kinda boring. You could glanc at Yahoo’s home page and see hoow thjey create news headlines to grrab people interested. You mighyt ttry adding a video or a related piic or two to get readers interested about everything’ve… Read more »

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