Mac Pro WiFi suddenly states "No hardware installed" but it worked yesterday.

Cilick on the apple in the top left and click "About this Mac". Click more info at the bottom, this will open an app called system information. Click system report and in the side bar scroll down to Network > Wifi. Click on that and look to se if there is anything listed under the "Interfaces:" section. If there is, this is a software problem that can be fixed pretty quickly, if there isn't, you might need a new AirPort card.

Regards!

Ri-dog

All kinds of weird fixes for this issue have been reported, most of which make no sense. I think it's usually or always caused by a hardware fault, which may be intermittent — something like a loose connector or a failed solder joint. Almost anything might seem to fix it, at least temporarily. In some cases, a software or firmware bug may be involved.

The Apple Hardware Test doesn't find anything, as usual.

To rule out everything but a bug or a hardware fault, take each of these steps that you haven't already taken:

1. Make sure all available updates are installed.

2. Reset the NVRAM.

3. Reset the System Management Controller.

4. Boot into Recovery by holding down the key combination command-R at the startup chime. In the OS X Utilities screen, select Get Help Online. A copy of Safari will launch. Test, then reboot as usual.

Also to AKtracks:

As Linc Davis says, weird fixes reported, "most of which make no sense."

This bedeviled me for over three hours. Many reviews of many leads that should've been fruitful, but weren't. None solved it. Happened to me upon a Turn Wi-Fi Off which, upon no alteration whatsoever, failed to turn back on. Or more correctly, icon was present in menu bar, but stated "No hardware installed." I'll be damned if I'm gonna get out screwdrivers to resolve that.

Donchaknow that I found this solution, which was absolutely my [and simplest of all] remedy:

http://macnerd-presents.blogspot.com/2011/08/os-x-lion-wifi-no-hardware-installe d.html

If one is addressing the issue, refer to that link.

In summary, I cite the site, "the solution is all about shut down options." Who woulda' figured?