I have tried to test the Arduino 2 Beta 3 IDE and it seems to be full of various bugs. Finally I have reached more or less the same state like you, but with more details, as I have used the verbose compilation output. May I ask you to try it again with the verbose compiler and share the result with us? And in addition – which CONTROLLINO variant do you have? And do you have installed also some old Arduino IDE (as you can see I have Arduino 1.8.3)?
Using board 'controllino_maxi' from platform in folder: C:\Users\Lukas\AppData\Local\Arduino15\packages\CONTROLLINO_Boards\hardware\avr\3.0.2
Using core 'arduino' from platform in folder: C:\Users\Lukas\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.3
I already thought that having both versiones installed could lead to problems and therefore I uninstalled all versions first and cleaned the “%localappdata” and “Documents/arduino” from all what remained from Arduino.
Then and I reinstalled the Arduino 2 Beta 3 IDE again.
At the moment I’ve given up, cleaned the system again and reinstalled the old version 1.8.3.
There’s real work to be done right now.
Can send you a photo of the setup in PM, if you’re interested.