What does "unsecured network" mean?

If all of the listed networks are secured (checked), the "wireless networks unsecured" alert may indicate another stored WLAN network. The alert is often caused by hotspots, hotel WLANs or other public networks.
You can manage the stored WLAN networks as follows:

1

Press the Windows key.

2

Click on "Settings" (gear icon).

3

Go to "Network and Internet".

4

Select "Wi-Fi" on the left side and click on "Manage known networks".

5

You will now see a list of saved Wi-Fi connections. Since Windows forwards all saved entries to us for review, the alert you described can be triggered by an unsecured Wi-Fi network. Remove the networks you don’t regularly connect to by clicking "Forget".