do i need to delete the default materials and such that come with UE4 to reduce disk size of the game?
When you package your project it should automatically ignore the assets that are not used in any of your maps. So you don’t need to delete them.
If i look into my packaged game, there are all files from the standard content, allthough i didnt use them. So deleting them seems to be necessary.
only this doesn’t seem to happen
It is supposed to happen but its not apparently. Delete all unused content manually for now.
Also it generates a giant Debug report wherever the outputted standalone.exe is and you need manually delete it.