Detectnow Option

Because waiting for detection to start can be a time-consuming process, an option has been added to allow you to initiate detection right away. On one of the computers with the new Automatic Update client installed, run this at command prompt:

wuauclt.exe /detectnow

Resetauthorization Option

WSUS uses a cookie on client computers to store various types of information, including computer group membership when client-side targeting is used. By default this cookie expires an hour after WSUS creates it. If you are using client-side targeting and change
group membership, use this option in combination with detectnow to expire the cookie, initiate detection, and have WSUS update computer group membership.

Note that when combining parameters, you can use them only in the order specified as follows:

wuauclt.exe /resetauthorization /detectnow

Windows Server Update Services (WSUS) Support Tools:

• Server Diagnostic Tool
• Client Diagnostic Tool

CLI for WUAUCLT:

• http://technet.microsoft.com/en-us/library/cc720477(WS.10).aspx

Source: http://technet.microsoft.com/en-us/library/cc708617(WS.10).aspx