Room mailbox unexpectedly disappears from an Outlook 2010 meeting invite


When you use Microsoft Outlook 2010 to organize a meeting and invite a Microsoft Exchange Server resource (room) mailbox to the meeting, all resource mailboxes that you added to the meeting unexpectedly disappear.

Note This problem only occurs when the Room Finder is visible.


This problem may occur for the following reasons:

  • The primary SMTP address of a resource mailbox that you add to the meeting contains an ampersand (&) character. For example, the SMTP address is R&
  • The added recipient has set his or her working hour range to span midnight (12:00 AM) in Outlook.


Use one of the following methods to resolve this problem.

Method 1: Install a hotfix update

To resolve this problem, install the following hotfix package:

2687392 Description of the Outlook 2010 hotfix package (Outexum-x-none.msp): August 28, 2012 

Method 2: Hide the Room Finder

To hide the room finder, click the Room Finder in the Options section of the Ribbon on the meeting item.

Method 3: Remove the ampersand character from the primary SMTP address of the resource mailbox

Contact the administrator for your organization to have them remove the ampersand character from the primary SMTP address of the resource mailbox.

Method 4: Change the working hours of the recipient so that they don't span midnight in Outlook

To change your work days and times, follow these steps:

  1. In Outlook, click the File tab.
  2. Click Options, and then click Calendar.
  3. Under Work time, select the Start time and End time of your work day. These are used primarily for your free/busy availability times for meeting requests from other people.
Note This is a "FAST PUBLISH" article created directly from within the Microsoft support organization. The information contained herein is provided as-is in response to emerging issues. As a result of the speed in making it available, the materials may include typographical errors and may be revised at any time without notice. See Terms of Use for other considerations.

Article ID: 2500176 - Last Review: 02/29/2016 19:11:00 - Revision: 10.0

Microsoft Outlook 2010, Microsoft Exchange Server 2010 Enterprise, Microsoft Exchange Server 2007 Enterprise Edition, Microsoft Exchange Online Dedicated

  • KB2500176