From time to time you may see your network profiles change to Public on their own. Windows doesn't make it very easy to change this via the GUI. Luckily, it's very easy to do so via PowerShell.

Step 1 - Find the network adapter's index by running the following command:

Get-NetAdapter

This will display a list of your network adapters. Look for the column titled ifIndex and note the index of the desired adapter. The next step assumes an ifIndex of 8. Replace with your actual index.

Step 2a - Set Private Profile

Set-NetConnectionProfile -InterfaceIndex 8 -NetworkCategory Private

Step 2b - Set Domain Profile

Set-NetConnectionProfile -InterfaceIndex 8 -NetworkCategory DomainAuthenticated