Wi-Fi

Use Wireless Diagnostics and wdutil on a Mac

Wireless Diagnostics is a Wi-Fi tool that comes with macOS. It analyzes the connection and lists problems with possible solutions. It does not change your network settings.

Applies to: All current macOS versions. The steps are from Apple's Mac User Guide for current macOS.Checked: 29 October 2026

Symptoms

The Mac reaches the router, but pages, email or streams fail.
Wi-Fi drops now and then, and you cannot find the cause.
IT support asks for a Wi-Fi diagnostics file.

Likely causes

Many possible causes. Signal, interference, router settings, DNS and software can all cause Wi-Fi problems. The tool checks many of them in one pass.

How to check

Quit all open apps.
Join the Wi-Fi network that has the problem.
Hold the Option key and click the Wi-Fi icon in the menu bar. Choose Open Wireless Diagnostics.
Follow the instructions on the screen.
In the Summary pane, click the Info buttons to learn more about each item.
To run the same tests from Terminal, use wdutil. The report goes to /var/tmp.
```
sudo wdutil diagnose
```
Needs an administrator password.
To show the Wi-Fi information without a full test, run wdutil info.
```
wdutil info
```

How to fix it

Apply the solutions that the Summary pane lists.
To find the report file, choose Go > Go to Folder in Finder. Enter /var/tmp and press Return.
The file name starts with WirelessDiagnostics and ends with .tar.gz.
Send the file to your network administrator or IT support, if they ask for it.
Also look for Wi-Fi Recommendations in the Wi-Fi menu. Apple says that it is not available for personal hotspots.

With Kilobat

For a fast check of Wi-Fi, the router, the internet and DNS, run Kilobat's diagnosis.
```
kilobat diagnose
```
For JSON that a script or an agent can read, add --json.
```
kilobat diagnose --json
```

Questions

Does Wireless Diagnostics change my settings?

No. Apple says that it does not change your network settings.

Does the report contain private data?

It contains details about your network and Mac. Send it only to people you trust.

Sources

Apple Support: Use Wireless Diagnostics on your Mac
Apple Support: If your Mac isn't connecting to the internet over Wi-Fi
wdutil(8), man page installed with macOS 27.2

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with man <name> in Terminal.