In July 2011, Microsoft acknowledged an intermittent query performance problem with all versions of Access and Windows 7 and Windows Server 2008 R2 due to the nature of resource management being vastly different in newer operating systems. This issue severely affects query performance on both Access 2003 and earlier with the Jet Database Engine code, as well as Access 2007 and later with the Access Database Engine (ACE). Microsoft has issued hotfixes KB2553029 for Access 2007 and KB2553116 for Access 2010, but will not fix the issue with Jet 4.0 as it is out of mainstream support.