DiskPeek

The question it answers: which app is using my disk right now?

What you see

Storage. A card for the startup disk with the read and write rates of your processes, a chart since you opened the screen and a capacity bar: space available (as Finder counts it) and how much of it macOS frees by itself when needed. Other local drives get a compact row, with a Low space badge under 10 % free. Network drives are skipped, and DiskPeek never looks inside your folders.

The launcher shows a Disk ring with how full the startup disk is and how much is free.

Activity. The busiest processes by disk activity. Each row shows its read and write rate over the last sampling interval and its total since you opened DiskPeek. Order them by what is busy right now, or by the total.

How to use it

1. Open DiskPeek. It takes a first sample, and rates appear with the second one a moment later.
2. Watch the top rows while you reproduce the slowdown, then open ProcessPeek to inspect the process.
3. Leave the screen and sampling stops. Coming back starts from a fresh baseline, so a rate is never computed over the time the screen was closed.

How it is measured

macOS keeps cumulative disk counters for every process. DiskPeek subtracts consecutive samples, at the refresh interval set in Settings (1 to 10 seconds), only while its screen is open.

• If a process’s counters go down (for example because the PID now belongs to a different process), DiskPeek starts a new baseline for it instead of guessing. You never see negative or absurd values.
• A process that appears between samples started inside the interval, so everything it did counts.

Good to know

• Other users’ and protected processes cannot be read, so they are not shown.
• The numbers show who is busy. They are not a byte-exact audit of the drive.
• It is not a disk-space cleaner, and it never scans your folders.

Privacy

Read-only; nothing is stored or sent. See permissions.