This is because "ShouldSave" is passed in via the Event Set Mesh, which isn't used in BuildWindow. So you need to add the call to save actor there just as it is done in the Build Master. You're right he didn't cover that and as a result windows aren't saving. (This is in addition to adding the Save Actor function if your window doesn't use the master

+1 :o) @@RainingPhoenixGames

Having the same issue, windows don't get saved either

There's a LOT missing for building windows, you need to implement all the events in "Build Interface" and other functions, which get used by the functions which call it from Third Person Character and elsewhere like UnsaveBuild / SaveBuild/ SetIsBuildFinished / SetMesh/ MultiSetMesh/ Event BeginPlay/ Multi_BeginPlay/ SaveActor/ RemoveFromSave.. I've so far (after 2 days) managed to get it to place a build (with one mesh wrong/one collider wrong on one window out of the two), save the build, reload the build, but when you interact with it I get 3 windows (lol) one opening in the wrong direction, and moving the build deletes it entirely.... Giving up for now and doing the rest of the videos!!! It's a lot of time to fix for me, also gotta work a way to get the foundation extensions to reload correctly! @@KJ-rc3io