Symptoms

Consider the following scenarios.

Scenario 1

  • You start Windows Internet Explorer.

  • You access a Microsoft Exchange Server 2010 mailbox by using Microsoft Outlook Web App.

  • You open a new tab in Internet Explorer.

  • In the new tab, you try to access a second Exchange mailbox in the same Exchange organization.

In this scenario, you receive an error message that resembles the following:

There was a problem opening your mailbox. You may have already signed in to Outlook Web App on a different browser tab. If so, close this tab and return to the other tab. If that doesn't work, you can try:
- Closing your browser window and signing in again.
- Deleting cookies from your browser and signing in again.


Scenario 2

  • You start a web browser other than Internet Explorer.

  • You access an Exchange Server 2010 mailbox by using Outlook Web App.

  • You open a new tab in the web browser.

  • In the new tab, you try to access a second Exchange mailbox in the same Exchange organization.

In this scenario, you may receive an error message that resembles the following:

This mailbox can't be opened. For more information, contact your helpdesk.

Cause

This issue occurs because a web browser cannot host multiple Outlook Web App sessions that access mailboxes in the same Exchange organization.

Workaround

To work around this issue, open a new session in the web browser. To open a new session in Internet Explorer, follow these steps:

  1. Start Internet Explorer.

  2. On the File menu, click New Session.


More Information

Tabbed browsing lets you view multiple web pages in a single Internet Explorer (Iexplore.exe) process. A new process is created when you start a new session in Internet Explorer.

Note Some other web browsers do not create a separate process when you open a new session.

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