You’re using group policy to enforce the “Run only approved Windows applications” for a specific group of computers such as terminal servers. After updating Adobe Reader from version 9.0 to 9.2, users receive the message: “This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.” My first thought was “The name of the executable must have changed”. A quick check disproved that. It is the same name with both versions: “AcroRd32.