Cause
You have inserted a device with distributed functions into the schematic. None of the functions is identified as a main function.
Note:
This message also appears if a single placed function is not identified as a main function.
Solution
Turn one of the placed device functions into a main function. To do this, double-click the appropriate component and switch to the Symbol / function data tab in the Properties <...> dialog. In the Function data (logic) group box, select the Main function check box.
Then start a new check run.