After deinstalling MF XP F3, We attempted to install Presentation Server 4.0 on a windows server 2000 SP4 server (as a member to a new created MPS 4.0 farm), but the installation stops with a message saying that: "Product: MetaFrame Presentation Server Components -- Error 10001. Installation of MetaFrame Presentation Server failed. Do you want to continue with the installation of the next component?" We check the msi-logfile and found the string "<CTX_MF_TestForInterOpMode. Return value 3 >" Action ended 12:14:38: CTX_MF_TestForInterOpMode. Return value 3. MSI (c) (B0:3C) [12:14:38:468]: Doing action: Fatal_Error Action 12:14:38: Fatal_Error. Action start 12:14:38: Fatal_Error. Action 12:14:38: Fatal_Error. Dialog created Does anyone know how to solve this installation issue ? Thanks ! Jan