Lists types of files that cannot be used offline.This setting lets you exclude certain types of files from automatic and manual caching for offline use. The system does not cache files of the type specified in this setting even when they reside on a network share configured for automatic caching. Also if users try to make a file of this type available offline the operation will fail and the following message will be displayed in the Synchronization Manager progress dialog box: "Files of this type cannot be made available offline."This setting is designed to protect files that cannot be separated such as database components.To use this setting type the file name extension in the "Extensions" box. To type more than one extension separate the extensions with a semicolon (;).Note: To make changes to this setting effective you must log off and log on again.
Network\Offline Files
Machine
Windows Server 2003 Windows XP and Windows 2000 only
HKLM\Software\Policies\Microsoft\Windows\NetCache!ExcludeExtensions
OfflineFiles.admx