Sorry for the lengthy delay in getting back to you. We are still unsure why Windows is not properly setting the .uproject association. If you could please download this file and save it to an empty folder on the desktop of one of the computers you are trying to put the Engine on. Remove the .txt extension and run the file. It will create a new info.txt file containing information about the computer’s registry keys that are involved in the process of associating the .uproject files with Windows. Please upload that new file so we can take a look at it.