Short answerIt depends on what you need the answer for:
- Apple Diagnostics (built in) tests the hardware — memory, logic board, battery. Free, and the right first step if you suspect a broken part.
- EtreCheck produces a thorough report of the software side. Excellent detail; you still have to read and act on it.
- Noah diagnoses the software side in plain English — one cause, one sentence — and then fixes it with your approval. Diagnosis and the plan are always free.
If you want to understand a report, EtreCheck. If you want the problem found and fixed without becoming the technician, Noah.
"Diagnostic tool" covers two different jobs. One tests whether the hardware is healthy. The other works out why a healthy Mac is slow, hot, full, or losing Wi-Fi. A non-technical person usually needs the second, and needs the answer in a sentence they can act on — not a 40-page report.
| What to look for | Apple Diagnostics | EtreCheck | Noah |
|---|
| What it checks | Hardware: memory, logic board, battery, sensors | Software and configuration, in depth | Software and configuration: processes, login items, disk, memory pressure, network, crashes |
|---|
| How you get the answer | A reference code to look up | A long report with severity markers | One cause, in one plain-English sentence |
|---|
| Needs you to interpret it | Yes — codes | Yes — the report | No |
|---|
| Fixes what it finds | No | No — it tells you what to do | Yes, one change at a time, after you approve it |
|---|
| Record of changes | N/A | N/A | Every change in the Action Log |
|---|
| Best for | Suspected broken hardware | A technical reader who wants everything | A non-technical owner who wants it fixed |
|---|
| Price | Free (built in) | Free to read; paid to unlock some features | Diagnosis free · $29 one-time or $79/yr for the fix |
|---|
Start with Apple Diagnostics if you suspect a part
A Mac that shuts off under load, a battery that lasts an hour, a screen with a line through it, a fan that never spins: those are hardware. Apple Diagnostics is built into every Mac and tests the parts. On Apple silicon, shut down, then hold the power button until you see the startup options and press Command-D. It gives you a reference code, and Apple's support page tells you what it means.
If the hardware passes and the Mac is still misbehaving, the cause is software or configuration. That is the job of the next two.
EtreCheck: the thorough report
EtreCheck gathers nearly everything about the software side into one report: what launches at login, kernel extensions, unsigned software, disk health, recent crashes. It marks the worrying parts, and it is widely used on Apple's own forums. It is a good tool. Its limit for a non-technical person is what comes next: the report tells you a login item is suspicious, and then you have to know what to do about it.
Noah: the diagnosis, and then the fix
You tell Noah what is wrong in your own words — "it's slow", "the fan won't stop", "it says the disk is full". It runs read-only checks on the Mac and answers with the cause it found. "A stuck Spotlight indexer has been at full CPU — the processor — for an hour." "Memory pressure is red because Chrome is using 9 GB." "iOS backups are taking 60 GB."
Then it proposes one fix, in one sentence, and waits. Nothing runs until you approve. Anything that removes data asks again and is backed up first. Every change goes in the Action Log. If the checks point at hardware, Noah says so and points you to Apple Diagnostics instead of guessing.
When Noah is not the answer
- You are technical and want the whole picture. EtreCheck's report is better for that, and free to read.
- You need proof for a repair claim. Apple Diagnostics' reference code is what Apple and repair shops recognise.
- The Mac will not start. Noah is an app and needs macOS running. Use Apple Diagnostics or macOS Recovery.
What Noah runs on
macOS 12 and later, on Apple silicon and Intel. The client is open source. There is also a Noah for Windows.
Try Noah freeKnow what's wrong, in one sentence.
Just tell Noah what's wrong:
Something's off with my Mac and I can't tell what.
Questions
What is the best Mac diagnostic tool for a non-technical person?
For hardware, Apple Diagnostics, which is built into every Mac and free. For a slow, hot, full or misbehaving Mac whose hardware is fine, Noah: it finds the cause on your Mac, explains it in one plain-English sentence, and fixes it with your approval. EtreCheck is excellent if you want a full report and are comfortable acting on it yourself.
How do I run Apple Diagnostics?
On a Mac with Apple silicon: shut down, press and hold the power button until you see the startup options, then press Command-D. On an Intel Mac: turn it on and hold the D key. It tests the hardware and gives a reference code you can look up on Apple's support site.
Is EtreCheck safe and free?
EtreCheck is a well-known, widely used Mac report tool and is safe. Reading the report is free; some features are paid. It reports and recommends; it does not make changes for you.
Does Noah replace a trip to the Apple Store?
For software and configuration problems, often yes: a slow Mac, login items, a full disk, Wi-Fi that drops, apps that crash. For hardware it does not. Noah tells you when the symptom points at a part, so you know to book a repair rather than keep trying software fixes.
How much does Noah cost?
Free to download. The diagnosis and the plan are always free. If you want Noah to carry out a complicated fix, it is a one-time Noah Pass for $29 or Noah Guardian for $79 a year, shown in the app before anything is charged.
Apple, Mac, macOS, Apple Diagnostics and Spotlight are trademarks of Apple Inc.; EtreCheck is a trademark of its owner. This page is an independent guide by the Noah team and is not affiliated with or endorsed by Apple or the makers of EtreCheck. Other products change often; check their sites for current features and pricing.