That’s the first line in google by request “disable f9 screenshoting”, so i’ll add extra solution here:
F9 screenshot is a debug binding that seems to be disabled in shipping builds; Nevertheless, there are cases where it need to be disabled in editor\development build and it’s not even in editor’s settings.
So: initially binding is defined in /engine/config/baseinput.ini, so to disable it we may edit project’s /config/defaultinput.ini to completely remove it for our project:
[/Script/Engine.PlayerInput]
-DebugExecBindings=(Key=F9,Command="shot showui")
In case you need to rebind it, you may write it in a following way:
[/Script/Engine.PlayerInput]
-DebugExecBindings=(Key=F9,Command="shot showui")
+DebugExecBindings=(Key=F10,Command="shot showui")
this way it’ll be rebinded from f9 to f10