When the editor has the auto-save prompt and mentions it is saving, it will instead do nothing. There is a warning message that prompts to the log if you read the “output log” window. UnrealEditorFortnite.log (2.0 MB)
To repro, place something in a project, wait for the autosave window to appear, let it save, then close the project. It will prompt you to save changes, even though auto-save should have done that.
Yes, the auto save is making a backup in another folder, so it won’t overwrite changes to the current level in the content browser. It could be made to overwrite the level in the content browser, but then if some kind of revision control software is not being used, autosave might overwrite the only existing version with some changes that weren’t meant to be saved. So we just save a backup elsewhere and leave the original untouched until a manual save is performed.
Thanks.