By default, your Mac automatically connects to WiFi networks that you had previously connected to. However, in case required, you can stop Mac from Automatically Connecting to WiFi Networks.
Stop Mac From Automatically Connecting to WiFi Networks
Once you connect to a WiFi Network on your Mac, it will remember the User Name, Password and other connection details associated with that WiFi Network.
This feature allows Mac to automatically connect to known WiFi Networks, whenever it is within the range of any previously connected WiFi Networks.
This can be useful, in case there are certain WiFi Networks that you occasionally connect to. For example, you may want to be able to connect to WiFi Network at Library, Place of work or some other place that you carry your Mac to.
However, it is also possible that you do not always use the internet from your Mac at these places (Library, Place of work) and do not want your Mac to automatically connect to WiFi Network at these places.
Irrespective of the reasons, it is possible to Stop Mac From Automatically Connecting to WiFi Networks, while still remembering the WiFi Network Name, Password and other connection details of other WiFi Networks that you occasionally connect to.
Prevent Mac From Automatically Connecting to WiFi Network
Follow the steps below to stop Mac from automatically connecting to WiFi networks.
1. Click on the Apple Icon from the top-left corner of your screen and then click on System Preferences option in the drop-down menu.
2. On the System Preferences screen, click on the Network option.
3. On the Network screen, click on the Lock Icon located at bottom left corner of the screen.
4. On the pop-up that appears, enter your Admin User Name, Password and click on the Unlock button.
5. Next, click on the WiFi option in the left pane and then select the WiFi Network that you want to modify in the Network Name box (See image below).
6. Once the desired WiFi Network is selected, Uncheck the little box next to Ask to Automatically join this network (See image above)
After this, you will not find your Mac Automatically connecting to this particular WiFi Network. In case there are more Networks, you can repeat the steps above to prevent Mac from Automatically connecting to those WiFi Networks.