Supporting windows 7

[wireless guy]

Hello,  Looking for a little help/guidance on an issue we are seeing on our wireless network.  We are a BYOD campus, so the client(b/g/a/n) can connect to wireless in building with 3602i, but not in building with 3702i unless we disable the 802.11n mode on the wireless adapter. WLC is 8540 code 8.5.135 building with 3600 ap's data rates support 12-54 and building with 3700 ap's data rates support 24-54.

[Leo Laohoo]

Is this happening to one client or a lot?

[wireless guy]

It’s the 5 one in the past month.

[Leo Laohoo]

Are they all the same machine (model) or various but all Windows 7?

[Scott Fella]

To add to what Leo mentioned, gather data on the machine, driver version, NIC model, etc and then determine if it’s specific to a certain variable or not. Typically a driver update is a good fix for these issues.  

Test also with different authentication methods, open, WPA2-Personal and WPA2-Enterprise and see if the device fails on one type of Auth. This way you are isolating the issue. 

[wireless guy]

I didn't get a chance to record the network card or laptop model.  So far all the machines we've encountered have been current on updates within Windows 7. It doesn't matter if they are single or dual band, wireless clients. The unique thing is it only happens in the buildings that have 3702 ap's.  They don't have issues with the 3600's or 3800's.

[Scott Fella]

Open a TAC case or scrub the bug tool for any identical issues. Most likely they will say to upgrade or downgrade the code. Seems like you must of upgraded since you mentioned the 3800’s and since Windows 7 has been out for a long time.

[patoberli]

WLAN adapter drivers don't get updated on Windows 7 through Windows Updates (typically). That means the user has to update them by himself. Intel had a LOT of really bad drivers out in 2015 (and parts 2014 and 2016). If those laptops never had a manual driver update since then, update those drivers.
There were also some really bad RaLink drivers at that time.
In any case, it's important to know the NIC type and driver version and date.