Part of macOS

`appstored`App Store downloads

○ Leave it

Downloads apps and updates from the App Store.

What it is

Handles App Store downloads, installs and purchases in the background.

Why it might be busy

While apps download or update. Usually until the downloads finish.

If you stop it

macOS starts it again straight away. Leave it.

○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.

From Procession’s guide, in the words the app shows.