macOS is designed to be as frictionless as possible. Whenever you connect to a public Wi-Fi network at a local coffee shop or an airport lounge, your Mac permanently memorizes the network name (SSID) and the password. The next time you walk within 300 feet of that building, your Mac will automatically disconnect from your cellular hotspot and violently latch onto the coffee shop’s terrible, 1 Mbps Wi-Fi connection without asking your permission.
This aggressive “Auto-Join” behavior causes massive disruptions during Zoom calls and file transfers. Instead of fighting your computer every time you walk down the street, you can dive into the Advanced Network Settings and explicitly revoke the Auto-Join privilege for specific, low-quality networks, while keeping the password saved just in case you actually need it.
Step 1: Open the Wi-Fi Settings
- Click the Apple logo in the top-left corner of your screen.
- Select System Settings (or “System Preferences” on older macOS versions).
- In the left-hand sidebar, click on Wi-Fi.
Step 2: Access the Advanced Network List
The primary Wi-Fi screen only shows networks that are physically near you right now. To modify a network from a coffee shop across town, you must access the master database.
- Scroll down to the very bottom of the Wi-Fi menu.
- Click the button labeled Advanced…
- A new window will slide open, displaying the “Known Networks” list. This is a chronological database of every single Wi-Fi network you have ever joined since you bought your Mac.
Step 3: Disable Auto-Join for the Offending Network
- Scroll through the massive list until you find the name of the terrible network (e.g., “Starbucks Guest Wi-Fi” or “Delta SkyClub”).
- Click the small icon with three dots inside a circle next to that specific network name.
- A hidden context menu will appear. Look for the option labeled Auto-Join.
- By default, there is a checkmark next to it. Click on it to uncheck it.
- Click Done at the bottom of the window to save your changes.
The Result
You have not deleted the password. If you ever intentionally want to use the “Starbucks Guest” network again, you can manually click it in your Wi-Fi menu, and it will instantly connect without asking for credentials.
However, by disabling Auto-Join, you have explicitly forbidden macOS from making that decision for you. Your Mac will now completely ignore the network as you walk past the building, keeping your current high-speed hotspot connection perfectly stable.