If this settings is enabled, when users with roaming prfiles log off, the system will delete the cached copy of their roaming profile. This will help to save disk space where that are lots of roaming users.
Key: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
Value Name: DeleteRoamingCache
Data Type: REG_DWORD
Data: (0 = disabled, 1 = enabled)