it doesn't work

Hi Leo. Sorry to hear the GU Replacement didn't work for you. I'm forwarding this discussion to one of my senior colleagues for analysis, and we'll get back to you as soon as we can with further thoughts. Thanks for bearing with us. 

Thanks for your patience. I've consulted with my senior colleague, Tim, who has loads of experience installing these operators in the field. He believes the issue might lie in the position of the mounting hole where the operator attaches to. If it's further away from the window jamb than the position of the one we show in our video, that would in turn screw up the ability of the operator to close the window properly. One solution in that case would be to try and attempt to re-position the stud bracket to make up the difference. The one risk you run with that though is if you re-position it too far, the operator will lose its ability to open and close properly. Still, it may be worth a try if this is indeed your issue. 

Some pictures of the where the hole the operator attaches to is, as well as how your old GU operator connected to the window, would be most helpful to further narrow this down.