Mac storage basics · Checking your storage
Why does macOS Storage settings say "Calculating…" for so long?
Short answer: It measures every category, which can take minutes after updates, on a full disk or during Spotlight indexing. Wait, then restart; rebuilding Spotlight's index can help.
Storage settings has to measure every category, which can take minutes on a full or busy disk, right after an update, or while Spotlight is re-indexing. Leave the window open for a while; it usually finishes.
If it never completes, restart the Mac and try again. Spotlight indexing problems can also stall it — rebuilding the index of the startup disk often helps. A storage tool that measures folders directly, such as Storage Studio's What's Using Space, can show you the picture while macOS catches up.