A look at how the macOS pasteboard, Universal Clipboard, and popular third-party clipboard managers actually store your copies in 2026 — what is logged, what crosses the network, and a five-step check to find traces of your last password. The short version: the pasteboard is global, Universal Clipboard is permissive, most managers store plaintext on disk, and you can audit all of it in twenty minutes with commands already on your Mac. What the macOS pasteboard actually is The "clipboard" on a Mac is an instance of NSPasteboard . The general one — NSPasteboard.general — backs Cmd-C, Cmd-V, the Edit menu, and every drag-and-drop. It is not an app feature; it is an OS feature exposed to every running process. What lives on it is more than text. A single copy can carry several representations at once: a UTF-8 plain string under public.utf8-plain-text , a styled public.rtf blob, a public.html rendering, file URLs ( public.file-url ), and image data for screenshots. The receiver picks whichever flavor it prefers.…