I have just bought a Vaio Pro 13 with the N 7260 card and made an upgrade to Windows 8.1 pro. I As soon as I install my VPN (IPSec) client software (made by AVM, but the shrew soft client produces the exact same result) the adapter does not connect on the 5GHz band. It still connects on the 2.4 GHz band without restriction and it also connects on 5GHz if I enable FIPS compliance but it is then restricted to 54Mbps.
This really bothers me because I need the VPN client software and I also need the bandwidth. On my old Vaio Z with a Intel WiFi Link 5100 AGN there is no problem at all (Win 8.1, same VPN client). So it must be down to the driver. I use the latest ver. 126.96.36.199. You need to fix this.
Thank you Joe. Maybe I should clarify that when I say the adapter does not connect on the 5GHz band it actually establishes a "limited" connection. It is unable to get an IP-address from the AP and of course it fails the Ping test if you run the diagnostics of the Proset software. I have not tested yet whether it would connect if I gave it a fixed IP address.
Also, as soon as I uninstall the VPN client software everything gets back to normal.
I have sent you a private message several days ago. We have a new wireless driver available: http://www.intel.com/support/wireless/wtech/proset-ws/sb/CS-034041.htm Intel� PROSet/Wireless Software; Intel� PROSet/ Wireless Software Downloads
If the issue is still present we would like to obtain more information about your setup, such as: