The short answer
Yes. Rebuilt or re-downloaded automatically when needed.
What is it?
Steam’s own cached data: store and library metadata, app information and statistics that Steam can fetch again from its servers.
What happens if you delete it?
Steam downloads it again at the next launch, so the first start is slower. Games and saves are not stored here.
How to remove it properly
Quit Steam completely, then move ~/Library/Application Support/Steam/appcache to the Trash. Clearing it is also a common fix when the Steam library displays incorrectly.
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
How MoreRoom helps
MoreRoom recognises this item, shows its real size and when it was last used, and labels it “Safe to remove”. In the free version you can move it to the Trash in one click, with Undo; Pro collects every safe item at once.
Frequently asked questions
Is it safe to delete the Steam appcache folder?
Yes. Rebuilt or re-downloaded automatically when needed. Steam downloads it again at the next launch, so the first start is slower. Games and saves are not stored here.
Will Steam app cache come back after I delete it?
Yes. Steam downloads it again at the next launch, so the first start is slower. Games and saves are not stored here.
How do I remove Steam app cache properly?
Quit Steam completely, then move ~/Library/Application Support/Steam/appcache to the Trash. Clearing it is also a common fix when the Steam library displays incorrectly.