Several users who are upgrading from Windows 7 or 8.1 to Windows 10 are allegedly facing Wi-Fi connectivity problems, especially on Cisco configured routers with old VPN client setup. Microsoft has already acknowledged that some bug in the router software is causing the Wi-Fi problem with devices running the Windows 10 upgrade.
It is confirmed that reboots and safe mode attempts on affected computers will not help fix this issue, as there are no wireless networks detected on the system even though the computer is within the range of known wireless networks. As a result, any random reboots or reinstallation of network drivers will have no bearing on the outcome.
"This issue may occur if older VPN software is installed on Windows 8.1 and is present during the upgrade to Windows 10. Older software versions contain a Filter Driver (the Deterministic Network Enhancer) which is not properly upgraded, leading to the issue," explains Microsoft.
Although Microsoft has not revealed any official fix for the issue at the moment, here's how you can restore Wi-Fi functionality for your device in Windows 10:
Step 1: Right-click on the start button and choose Command Prompt (Admin) from the menu.
Step 2: Input the following command at the prompt and hit the Enter key:
reg delete HKCRCLSID{988248f3-a1ad-49bf-9170-676cbbc36ba3} /va /f
Step 3: Then type in the following command at the prompt and press Enter again:
netcfg -v -u dni_dne
Step 4: Just restart your computer and verify the Wi-Fi settings. You should now be able to track all available Wi-Fi networks in range and connect to them flawlessly.
[Source: Redmond Pie]
