Luckily it's easy to stop this happening and we'll run through ways to do it on Windows and Mac in this tip.
Firstly, open System Preferences from either the Apple menu at the top left of the screen or from the Dock. Then click on the Network icon.
Once the network options are open, click on the WiFi connection on the left hand side and then click on Advanced.
You'll now see a list of all the WiFi networks your Mac has connected to, simply click on the one you want to remove and then click on the minus icon just under the list.
Now click on OK to close this window and click on Apply on the next window. You can now close System Preferences and your Mac shouldn't try to connect to that WiFi network again.
Windows 10On Windows, all you need to do is click on the Start button and then click on Settings.
Once the Settings window opens, click on Network & Internet.
On the screen that appears, click on WiFi on the left hand side and then Manage known networks.
Now just click on the network that you want to remove and click on Forget and your laptop will no longer connect to that WiFi network in the future.