We are currently seeing an issue related to users on Windows XP and Outlook 2007/2010 accessing a mailbox on Exchange 2010 from multiple copies of Outlook. We have an open case with Microsoft regarding this issue. Microsoft has been able to reproduce this issue, and they have multiple teams investigating it. They have not released a public KB regarding this bug, and we do not have a hotfix for the issue from them yet. Microsoft has confirmed that this is not an issue for Windows Vista or Windows 7 operating systems and we have confirmed this with our own testing.
If you are using Outlook 2007/2010 on Windows XP to access the same mailbox from multiple locations and you are experiencing connectivity issues, please review the following Knowledge Base article for workarounds until we receive a fix from Microsoft. This issue will also occur if you are using a resource mailbox from multiple copies of XP.
Solution Consultant, Hosted Exchange
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