The operation failed error when you send email messages in Outlook

Original KB number:  3028159


When you send email messages in Microsoft Outlook, you receive the following error message:

The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook.


This issue occurs when a Google Apps Sync for Outlook account and an Exchange Server account are configured in the same Outlook profile.


Don't configure an Exchange Server account and a Google Apps Sync for Outlook account in the same Outlook profile. Instead, create separate Outlook profiles, and then configure the Google Apps Sync for Outlook account in one profile and the Exchange Server account in another profile. This Microsoft Knowledge Base article describes how to create profile and set up an e-mail account in Outlook.

More information

For more information about this issue, go to the Google Apps Known Issues page, and then expand the "Email Clients and Mobile Devices" section.

Third-party information disclaimer

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

Third-party contact disclaimer

Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.