/Type=ShadowType /For=ForVolumeSpec /Oldest /Quiet %1 %2 /Shadow=ShadowId /Quiet - For the given ForVolumeSpec deletes all ...

%1 %2 [/Type=ShadowType] [/For=ForVolumeSpec] [/Oldest] [/Quiet]
%1 %2 /Shadow=ShadowId [/Quiet]
     - For the given ForVolumeSpec deletes all existing shadow copies 
     satisfying the given options.  If /Oldest is given, the oldest matching 
     shadow copy on the volume is deleted.  If /All is given without a 
     ForVolumeSpec, all shadow copies on all volumes that can be deleted are 
     deleted.  If /Shadow=ShadowId is given, the shadow copy with that 
     Shadow Copy ID is deleted.
    - The Shadow Copy ID can be obtained by using the List Shadows command.
    When entering a Shadow Copy ID, it must be in the following format:
       {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} 
    where the X's are hexadecimal characters.    This ID can be obtained 
    through the List Shadows command.

    Example Usage: vssadmin Delete Shadows /Type=ClientAccessible /For=C:

                   vssadmin Delete Shadows 
                            /Shadow={c5946237-af12-3f23-af80-51aadb3b20d5}

    - Valid shadow copy types: