El Capitan, Wifi 5GHz Enterprise Issue

Hello,

I have been trying to connect to the WIFI router in my office at the University I work at. I am able to connect to the router in my office, however, without Internet. Sometimes, though, I am unable to connect to the router at all. It really just depends. Then, all of a sudden, the Internet will resume working, and I will regain full access again. (Every other access point on campus works with my machine just fine, but read below...)

After trying all troubleshooting options in configuration, etc., both with IT on campus and with the many troubleshooting suggestions online, I finally realized that this only happens when I connect to the 5GHz broadcast on the school routers. It is the 2.4GHz broadcast that works just fine. Thus, in my office, I am connecting at 5GHz initially, but without Internet. Then, after some time and troubleshooting, my machine connects at 2.4GHz and my Internet is restored. I would like to conclude that there is some sort of configuration/Yosemite problem with my machine when connected to the school network on the 5GHz broadcast. However, my wife has the most recent release of the rMBP 13", and she is running the same version of Yosemite, and she connects just fine to the 5GHz broadcast on campus, including to the router in my office. What's interesting is that I immediately connect to all other access points on campus at the 2.4GHz broadcast, but in my office, at the 5GHz broadcast, and with unreachable Internet. (The access points are all identical, by the way.) My wife's macbook, however, immediately connects to the 5GHz broadcast on the same access points with reachable Internet.

Has anyone else had a similar issue, specifically with the rMBP 15" (Late 2013) model? Is there anyway it could still be a configuration issue with my machine? Could it be a hardware issue with this rMBP model (Late 2013) and the wifi hardware therein?

Processor: 2.3 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Graphics: Intel Iris Pro 1536 MB

Thank you.

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I resolved this issue by reverting the IO80211Family.kext extension file in /System/Library/Extensions to a previous version from the current one in Yosemite. I replaced the current file with a version labeled 7.0 from a TimeMachine backup that I had saved. This gave me immediate access to the 5GHz broadcast with Internet on my rMBP (Late 2013). I am on a Juniper Wireless router, WLA522, on a school enterprise network.

In any case, this solved the issue for me.

N. French

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After updating last night to Yosemite 10.10.5, my wireless problem resumed. Just so I am clear, previously, I attempted all troubleshooting suggestions for this issue. The only one that worked is this one:

I resolved this issue by reverting the IO80211Family.kext extension file in /System/Library/Extensions to a previous version from the current one in Yosemite. I replaced the current file with a version labeled 7.0 from a TimeMachine backup that I had saved. This gave me immediate access to the 5GHz broadcast with Internet on my rMBP (Late 2013). I am on a Juniper Wireless router, WLA522, on a school enterprise network.

This resolved my issue again today by restoring the newly updated IO80211Family.kext file to a previous version (7.0) via the Time Machine backup. I do hope this issue is fully resolved by Apple in the El Capitan update.

N. French

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My issue has now returned in El Capitan.

I tried to apply the above fix, but received a warning message telling me that El Capitan will not allow me to replace the system file. All other MacBooks and Apple Devices connect to this router in my office except for this model rMBP (Late 2013) and a rMBP (Mid-2012).

I am convinced that there is a hardware malfunction with the system configuration that Apple has built into OS X system file IOS80211Family.kext after its 7.0 version that renders my rMBP WIFI hardware useless on these sorts of Enterprise systems running at 5GHz.

I was told at the Genius bar, after my machine connected to their 5GHz network just fine in the Apple store, that it's the University environment that is the problem. But again, I am not satisfied with this answer since it is only certain models of rMBP that cannot connect due to versions of this system file that are beyond the 7.0 release. And the behavior on both of these machines (rMBP Late 2013 and rMBP Mid 2012) are identical as it pertains to this issue.

Any ideas of what I can do? Must I sell this machine and purchase a newer one?

N. French