It's really weird: sometimes it works without an issue and then it suddenly refuses working again. And I never should touch the startet acti.exe (alt+tab to desktop etc.) to load the live telemetry window - then the application frontend crashes without notice and I get the errors back until I reboot my system and start from the scratch. I doubt it has something to do with other apps but I will check this. Maybe there is something going on with the codepages? And I am running the 64bit version of AC as I have a 64bit windows (german version, european codepage 850).
Edit: Did a short test today with all other custom apps disabled and it worked from the very beginning. I could do some test laps wothout any issue and as soon as I re-entered to the box it saved and exported the session. Quite very well!
But as soon as I switched to the desktop and tried to open the Live Telemtry viewer, too, the acti.exe crashed and I could‘t get it to work again until I exited AC and restartet new.
Maybe this behavior has something to do with the fact that I am running a 2-screen system with the main screen running AC in full view and the additional screen for seperate tools like TS oder HudDash communications programm (but both were not running during this test session!) etc.