Hello community,    I am new to the X-Plane world ;-)   After trouble-free installation of the FF 757 and Amsterdam, nor the Saab 340A should enrich the hangar.  Bought, installation, end. X-Plane (64 bit) will not boot ...  "Fatal Error SteamAPI_Init () failed ..."   I use X-Plane via Steam ;-) Apparently, the Saab and Steam do not like?    The most important insight -> if the "Gizmo64.plugin" removed from the resources / plugins folder, X-Plane starts again.  If I read correctly, the Saab needs this plugin to work?    A few more information to isolate the problem:  - Only the 64-bit version does not start  - Steam is of course connected  - X-Aviation credentials are entered correctly when installed  - X-Plane checked via Steam on error -> no change  - Installation of Saab to run again -> no change  - Loaded latest version of the plugin Gizmo64 - -> no change  - Mac OSX Firewall is disabled -> no change    Attach Files: GizmoLog.txt & Log.txt     Someone further ideas or even the remedy?      Preliminary ever thank you!    Christian     PS: thank you google for the translation :-) GizmoLog.txt Log.txt