A session pool leak occurs when a desktop sharing application runs on a Windows Vista-based or Windows Server 2008-based computer
Assume that you run a desktop sharing application on a computer that is running Windows Vista or Windows Server 2008. For example, you run Windows Remote Assistance. In this scenario, a session pool (HT40 tag) leak may occur. Additionally, after you log off the computer, the session pool is freed.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB2523126.