Ui extension is associated with User Interface. You may try to open ui files with Note Pad application.
It is an interface file that related to many updated softwares. When you run ui files with relevant software all the menu looks and icon images change.
To open and use ui files, it should be installed with relevant softwares menu. You should select Load command from the user interface menu. To save ui files you should pick the save command from the same menu.
What to use UI
which page related to UI file
UI Related Searches
You can check related links about UI fileextension.