Then either use the button in the toolbar or Build -> Create Executable.
I, too, am having the same issue as
@TomCartwright. Whether I use the keyboard shortcut or the button in the toolbar or the application menu, there is no response from the IDE at all. I cannot build an HTML5 executable.
I have no issues running an HTML5 project using F5. I am using the latest version of GMS2 on macOS 11.0.1.
Can anyone provide any insight?
EDIT: Strange. Creating HTML5 executables started working just fine all of a sudden. Not sure why. I'm good now.