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

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Outlook 2007, Exchange 2007, cached mode, user tries to save a message with a pdf attached and receives the message below - I have recreated the outlook profile twice and its not a pst file.

" The messaging interface has returned an unknown error. If the problem persists, restart Outlook. "

any idea's? thanks.

Evan Liu


I want to clarify the following information before we go further:

1. Does this issue only occurs to one user or all the users who connect the Exchange Server?

2. How about the other versions of Outlook, does this issue also occur on them?

3. Do you installed all the latest updates for your Outlook? If not, please install the latest updates and have a try.

4. Does the issue only occur when you try to save a message with a pdf attachment or whenever you use Outlook?

5. Is there any error in your event log, if there is any error in your event log, please paste here in your next post.

6. What is software you used to save a message with a pdf attached?

If you use Adobe Acrobat, this issue may occur because the version of Adobe Acrobat that you have installed is incompatible with Outlook 2007. Here is a related article for you:

Acrobat PDF functionality is missing, or Outlook closes unexpectedly after you upgrade to Outlook 2007

If not, please help me to collect the information at your convenience, with the information, we can help you more efficiently.




1) one user

2) we only use 2007

3)sp2 is installed

4) issue also happen without an attachment but with error -

“Operation failed” when I tried to save an email with no attachments as a .rtf

5) get back to you on that

6) Outlook 2007

I'll check the article


Hi route666, here are some tips. (It sounds like the problem is not related to any specific attachment)
Check mailbox size of the user and compare it with any limit restrictions you may have set on the Exchange Storage group container where the users mailbox resides in.

If the mailbox is full you can get all sorts of weird messages..

Check the size of the mailbox and then compare it with any applied limits.

you can check the limits on two places the default global policy on the exchange server

in the " Exchange System Manager" console right click the storage group that she belongs to and check the page " limits"

also check the account in the AD the " Exchange general" page and then the button " Storage limit" .

If it is short on space increase limit and tell user to clear out som big sized e-mails.

AD account settings overrides global settings.
You can also try this but the user will loose Outlook specific settings configured by the user.

Try some outlook switches..

try for example run:

Outlook.exe /cleanprofile

Removes invalid profile keys and re-creates default registry keys where applicable.

With best regards Gorgis


thanks for the info. one question, how does the /cleanprofile differ from creating a new profile?


Sorry I can´t say as I dont know the details about the diffrens, but if you didn´t try it yet it is worth a shot as its simple to try.

has more about Outlook switches.

- My first tip about storage limit gave no results?

- Did you also try to delete the users *.OST file completely so that i will be recreated? (if file is corrupt, Outlook must be closed when deleting as Outlook looks the file when started.)

- How does the attachments and e-mail behave when using the webinterface/OWA?

(%Name of the outlook profile%.ost)

will be located under the user windows profile..

With best regards Gorgis


the mb is 25 meg below the limit.

I have recreated the profile so that recreates the OST.

I asked the user to try OWA when the issue pops up again (and to call me).

after, the OWA test, I will do a /cleanprofile.

thanks for your help.


25 mb is not so much, maybe the user just recently did a clean?

Check with the user if he has deleted any large e-mails/attachments recently..

I strongly suggest incresing the users margins to at least 100 mb more at minimum and tell the user to clear deleted items if it is not done allready.

Then to sort/filter on size on all of the inbox inorder to recognize the largest e-mails and to save them to disk/network storage and then have them removed from the inbox. (Dont forget to purge the deleted items after this action)


With best regards Gorgis

Evan Liu


Any updates? If this problem persists, please share us the result after you try. With the result, we can help you more efficiently.


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