Well i must admit i was new to UE4 and I didn’t know that compiling would include all assets - even the ones that are not used.
I’ve always thrown complete asset folders into my project and picked a few i could use. In the end i had a few gigabyte unused assets in the folder - which didn’t bother me much until i cooked the project the first time…
So is there a tool/script/plugin/whatever to remove unused assets?
A trick I use to scrub the project level is under Window > Levels you can select the Persistent level and migrate it to a blank project. This process will “only” migrate active assets being used in the project environment.