[WiFi] Wireless adapter troubleshooting tips

Bypass USB extension cable and/or cradle/hub (if in use).
On desktop computer(s) connect the adapter to the rear ports. Issue may be related to USB bus for front ports.
Update USB controller drivers. (Check motherboard/logic board manufacturer OR computer manufacturer website for latest drivers)
Make sure adapter is plugged in correctly (light should turn ON when adapter gets powered.
If adapter is not recognized after computer is woken up from sleep mode or hibernation, disable power management support on the adapter properties. Computer may not be loading the drivers properly after waking up from sleep/hibernation; this is more of a computer related issue. If power management is disabled the adapter will stay powered ON with drivers loaded.
Test the adapter on a different computer (if possible) to verify whether it is working or faulty.

Newer Windows operating systems (Win10) have a lot of drivers built-in to the OS, chances are the device will be installed automatically when plugged in.
HQ needs to be contacted to see if drivers will be created to support newer OS.
Last option would be to check with chipset manufacturer to get their latest driver update. If chipset manufacturer (ex: Broadcom, Qualcomm Atheros, Realtek, etc.) decides not to support the OS, Zyxel will not support the OS either.

If computer is running Windows XP or newer, only driver should be installed. Zyxel Wi-Fi Utility does not need to be installed as Win XP and newer have their own native utility. Having the Zyxel utility installed can create a conflict with the native Wi-Fi utility which will cause disconnects.
On desktops use the rear USB port, these are more stable and reliable when communicating with USB adapters. Ports in front may be using a different USB controller than the one built-in to the motherboard/logic board.
Bypass USB extension cables and or USB cradles/hubs.

Verify the IEEE 802.11 wireless technology being used in your network. Performance depends on the wireless technology being used.
Check security on wireless base station. Newer wireless technology, 802.11n/ac, do not support legacy encryption algorithms. IEEE802.11n/ac require WPA2-AES or better to reach their maximum theoretical speeds. Using older security methods such as WEP, WPA-TKIP will force wireless base station to use legacy 802.11 wireless technologies (802.11a/b/g).
Match wireless technology. Disable legacy bands if not in use.
Performance is dictated by the wireless base station, not the client. The client will provide the wireless base station with information on what bands and speeds it supports, then it is up to the base station to specify what band and speed will be used for their communication.
Check the distance and obstacles between the client and wireless base station. The clearer the path the better the performance will be.
Try different DNS servers to resolve domain names. If DNS servers take too long to resolve and respond to your computers queries, it may take long to open websites.