Ok, new clean install with the same problem, but now in the Log.txt <I can find:
"dlerror:dlopen(/Applications/X-Plane 10/Resources/plugins/X-IvAp-64.xpl, 6): Library
loaded: @rpath/libfmod.dylib
Referenced from: /Applications/X-Plane 10/Resources/plugins/X-IvAp-64.xpl
Reason: image not found
Failed: /applications/X-Plane 10/Resources/plugins/X-IvAp-64.xpl. (This file is missing) or not a DLL or could not be loaded due to another missing DLL.)"