external mac keyboard not working with maverick on macbook air

I'm having the same exact issue with my IMac. The extension cord trick didn't work, so I'm not sure what to do next. Based on what I'm reading here, I'm wondering if it has something to do with the El Captain update. Should I uninstall it?

Add another to the list. Late 2014 Retina iMac and just had it happen again for the 3rd time in about a year. Have an external Apple monitor through Thunderbolt that has a couple USB ports on it and moved the keyboard over to that to get it working again. In a couple days I can plug it back in to the main iMac and it'll work again.

I had just unplugged it to clean the keyboard and couldn't get it to work in any USB port on the iMac afterwards but works fine on the external monitor. Latest OS, Apple USB Extended Keyboard. Incredibly annoying, but happy to have found this thread again (I had forgotten how I'd gotten it to work again previously).

iMac (Retina 5K, 27-inch, Late 2014)

10.11.4 (15E65)

Keyboard A1243 - Apple USB Extended Keyboard

The keyboards are garbage.

They changed the design.

Basically if you strip one down you will see at the top edge right in the middle they have a membrane connector that turns & folded 90 degree back on its self.

This is hard against the aluminum, which bends top to bottom, no support other than plastic back., the connector then micro cracks the silver conductors, which make & break conenction randomly.

Now it works for a few months , now it does not.. Simply moving of flexing the KB or an impact can cause it to go.

Also they will not replace, one apple shop told me the "serial number" was the model number.

I pointed out that 2 different KB had different serial numbers, they said it was old model & new model, the serial numbers are also NOT in the apple database.... oh what a surprise.....

I have a late 2013 imac running the latest El Capitan. My brand new extended USB keyboard stopped working with the computer. Genius Bar had no idea what was happening so they replaced the new keyboard with another new keyboard. I had been doing PRAM restarts with no positive effect. I took the computer in and we could not reproduce the problem by restarting and shutting down and restarting.... so they did a reformat on the computer reinstalling the OS and the computer was wiped clean. Took it home and after 3-4 weeks the keyboard issue was back not responding. So I found this thread... THANK YOU. The new USB keyboards you buy now have a short extension cord. I tossed that aside not knowing why it was there... I had it the whole time. The Genius Bar did not tell me I needed it. I thought it was for plugging in OTHER THINGS and not for the keyboard... so I feel dumb. Why does the extension fix it? Why did the Apple people not know of it to tell me? Why did Apple Care on the phone not ask me about the extension? Also why is the communication within the company to the customer so bad on this issue? This computer was very expensive like 3000 dollars and I would expect better communication and knowledge of this issue that is seemingly becoming rampant.

I have a late 2013 imac running the latest El Capitan. My brand new extended USB keyboard stopped working with the computer. Genius Bar had no idea what was happening so they replaced the new keyboard with another new keyboard. I had been doing PRAM restarts with no positive effect. I took the computer in and we could not reproduce the problem by restarting and shutting down and restarting.... so they did a reformat on the computer reinstalling the OS and the computer was wiped clean. Took it home and after 3-4 weeks the keyboard issue was back not responding. So I found this thread... THANK YOU. The new USB keyboards you buy now have a short extension cord. I tossed that aside not knowing why it was there... I had it the whole time. The Genius Bar did not tell me I needed it. I thought it was for plugging in OTHER THINGS and not for the keyboard... so I feel dumb. Why does the extension fix it? Why did the Apple people not know of it to tell me? Why did Apple Care on the phone not ask me about the extension? Also why is the communication within the company to the customer so bad on this issue? This computer was very expensive like 3000 dollars and I would expect better communication and knowledge of this issue that is seemingly becoming rampant.

strange and thank you

Hi! I have done all the resets that in this post the people suggest and nothing works. However, after I use the extention of the USB my keyboard works fine. So, I talked with my IT guy in my office and he suggest the next thing:

After we plug any USB device (USB Memories or Keyboards) the machine install drivers in our computers to control our devices. Therefore, if we erase this driver (the one that creates for our wired keyboard) and plug again the keyboard, that should works because the mac will create a new driver so our keyboard will work again.

Therefore, is there any User that can show me were are this drivers (USB, Keyboards, screens) so I can erase them and try this solution?

My IT do not have a mac that why he is no able to help me with this (He is a Linux and windows user). Please let me know.

How in the world does this bug still appears on a $ 5k TouchBar retina MacBook Pro and macOS … *sigh*

@apple … what the heck is the issue here?! :-(

System > Library > Extensions > AppleUSBTopCase.kext ...