Windows 7 devices: Slow or no DHCP refresh, cant connect to wifi at all, require wifi card resets, ever since the most recent upgrade.

unknown

As the description states:
Ever since the most recent upgrade, all of our Windows 7 users across several organizations are having problems.

It doesn't matter whether they're attempting to connect to our Public Wifi with a static shared pass or or private wifi using their WPA2-Enterprise RADIUS credentials. 

Everything was working until the major upgrade. 

Resolution requires re-installing the driver on said devices sometimes once a day. 
All of these wireless devices are not having similar issues anywhere else. 

Can someone help? Is this a known issue?

unknown

can you give us more details? controller? ap type? errors? work arounds?