the unit was defective
Is the unit small?
Installed on system running Windows 7 x64 Ultimate.  Had ZoneAlarm Security Suite installed and the installation software would install but the unit would not see my router.  Contacted TP-LINK and after talking to one of their phone support tech, had gotten an RMA assuming the unit was defective.Not really wanting to ship the unit back to TP-LINK for a replacement, I did a bit of internet research and discovered that this unit has issues with ZoneAlarm Security Suite.  The write-up recommended uninstalling ZoneAlarm, installing the driver, then reinstalling ZoneAlarm.  I uninstalled ZoneAlarm and it took Windows 7 out with it.After reinstalling Windows 7, the TL-WN822N came up with signal strength 5 and is now working fine. 