Native app for macOS 26
Your Mac has been backing up quietly for weeks. Time Machine Monitor reads its records and tells you what it never does — how big each backup is, exactly what changed, and whether any quietly failed.
macOS 26 · Apple silicon · Developer ID signed & notarized
What it shows you
It only lets you restore. This tells you how your backups are actually doing — and where your space is going.
Time Machine records exactly how much each backup changed. Monitor reads that ledger directly — no hours-long disk crawl — so every backup's size and file count are there the moment you open it.
Time Machine tries, fails, and says nothing. By comparing attempts against completions, Monitor surfaces the ones that never finished — a gap even Finder won't show you.
Pick two points in time and see precisely which files were added, modified, or removed — down to the byte, powered by Time Machine's own compare engine.
Trace one file across your whole history — when it changed, how big it was each time, and pull any past version back out.
A menu bar item that turns amber the moment a backup is overdue or the destination fills up. Green means you can stop thinking about it.
Backing up to a NAS? Monitor is built for slow, encrypted SMB destinations — every read is streamed, cancellable, and cached, so it stays quick.
Why it's different
Backup sizes are genuinely hard — APFS clones and hard links make a naive measurement wrong by orders of magnitude. So Monitor is careful about what it claims, and labels every figure by how it was obtained. When a number would be a guess, it says so instead.
The same principle runs the whole app: it reads Time Machine's own records, never fabricates precision the data can't support, and does everything on your Mac.
Under the hood
No scanning your disk, no analytics, no account. It leans on the records macOS already keeps — the only thing it ever sends is an update check, and only if you allow one.
Time Machine keeps a manifest of every backup's exact size and file count. Monitor reads it — one file, not a disk crawl — so sizes appear instantly.
Ask what changed between two backups and it runs Apple's own comparison, streaming and caching the result so you never wait for the same answer twice.
A tiny menu bar presence tracks cadence and capacity, flagging overdue or failed backups the moment they happen — and staying out of the way otherwise.
Support development
Time Machine Monitor is free and independent. If it has spared you a backup scare, you can chip in toward its upkeep — no pressure, and no features locked behind it. Contributions are voluntary and non-refundable.
Free while in development. Signed with a Developer ID and notarized by Apple — a clean double-click install, no Terminal required.
Requires macOS 26 Tahoe · Apple silicon · 7.4 MB