Maximum number of recent documents
Supported on: Windows Server 2008, Windows Server 2003, Windows 7, Windows Vista, Windows XP, and Windows 2000
Registry
HKCU
Software\Microsoft\Windows\CurrentVersion\Policies\Explorer Options
MaxRecentDocs decimal Description
"This policy setting allows you to set the maximum number of shortcuts the system can display in the Recent Items menu on the Start menu. The Recent Items menu contains shortcuts to the nonprogram files the user has most recently opened. If you enable this policy setting, the system displays the number of shortcuts specified by the policy setting. If you disable or do not configure this policy setting, by default, the system displays shortcuts to the 10 most recently opened documents."