Uninstall ProSet from Control Panel. Restart.
Install this driver: https://www.crc.id.au/files/Intel%20AC-7260%20v220.127.116.11.exe
In the advanced properties of the adapter, try these:
802.11n Channel Width (band 2.4/band 5.2) Both Auto
Ad Hoc Channel 802.11 b/g 1
Ad Hoc QoS Mode WMM Enabled
ARP ofload for WoWLAN Enabled
Bluetooth® AMP Enabled
Fat Channel Intolerant Disabled
GTK rekeying for WoWLan Enabled
HT Mode VHT Mode
Mixed Mode Protection CTS-to-self Enabled
NS offload for WoWLAN Enabled
Preferred Band Whichever. I don't think it matters.
Roaming Aggressiveness Medium
Sleep on WoWLAN Disconnect Disabled
Throughput booster Disabled
Transmit Power Highest
U-APSD support. Enabled (Some peeps need to disable this for better speed--I don't know why.)
Wake on Magic Packet Enabled
Wake on Pattern Match Enabled
Wireless Mode 802.11 a/b/g
In the Power Management tab, set "Allow the computer to turn off this device" to ENABLED. It's counterintuitive, but just do it.
Try these router settings:
11bgn mixed mode
Channel width auto
SSID broadcast yes
Short GI enabled
Client isolation disabled
11a/n/ac mixed mode
Channel width Auto
SSID broacast yes
IMHO Intel ProSet is extremely user UNfriendly
After wasting hours fighting with it I switched to Windows Wireless Connection Manager and my problems have ended for good!
You need about 10 seconds to switch and end the suffering
Disabling the Intel PROSet Wireless Utility
Locate and right click on the Intel PROSET Wireless utility icon located at the lower right corner of your Windows Desktop.
Select Use Windows to manage WiFi on displayed on the menu options.