Note: An exception to this behaviour occurs when you edit in Prefab Mode. In this case, File > Save only saves changes to the open Prefab. It does not save Scene changes or Project-wide changes.
Unity also saves some information immediately while you’re working in the Editor. See Immediate saving, below, for more details.
Scene changes include modifications to GameObjects in the Scene, such as when you:
Project-wide changes in Unity apply to your whole Project, rather than a specific Scene. If you want to save Project-wide settings without saving Scene changes, go to File > Save Project. You might find this useful if, for example, you create a temporary Scene to test some changes.
Project-wide changes include:
There are some changes which Unity immediately saves to disk when they happen. These include the following: