I have been using FM version 3 for years with ACP without issue and just upgraded to FMV4. I have configured FM for MaxIm, Robofocus Sever for the focuser, and ACP Telescope Hub. Version 3 was simply set for MaxIm and RoboFocus Server and worked reliably. With V4 I edited my startup script to point to V4 directory and changed the setting in ACP Prefs for the default FM ini file location. All goes well enough on startup until ACP calls for the initial focus. It locates, slews, and plate solves the focuser image but then the routine fails, attempts to focus again and fails. It's unclear to me from the help files in FM V4 what else might need to be done. I don't use the Acquire Star feature in FM so I'm not connecting to the telescope. Any suggestions would be gladly tried while I still have a bit of hair left. And that's not as funny as it use to be! ):