I upgraded to Windows 8.1 using the Microsoft Store two months ago.
Since then I have two problems with my Envy:
-It can only detect 2.4G WiFi networks, and nor 5G networks. Mine is missing (fortunately I have both signals), and I used it before with this HP Notebook under Windows 8.0. The 5G WiFi network is working properly because is available for all my other devices.
-I have problems with my bluetooth keyboard, because once it is paired, It becomes crazy, repeating keys (as it was battery low, and this is not true because I changed them, and I can use the same keyboard with other devices, and it works properly). So the only reason for this issue must be the driver.
Now, I disabled the internal bluetooth device, and I attached a external Ovislink bluetooth USB dongle, and my keyboard is working perfectly. That confirm that the keyboard works properly.
I tried to install the new drivers published by HP, and none solves both problems.
I manually unisntall the drivers and I used the HP Suppor Assistant wizard, and It automatically installed the proper drivers, and It didn't work too.
So, I suppose that both drivers must be updated by HP...
Someone recommended me to uninstall Windows 8.1, and go back to Windows 8.
I think that this is not the solution.
In the meantime, i'm working under 2.4G wireless networks, and using an external bluetooth USB dongle.
Regards