Apple USB keyboard does not work

I have had the same problem, but only after restarting the imac (mid 2011 21" model). Today, I couldn't get it connected in any possible way. Tried a logitech usb-keyboard I had here, that worked perfectly. Tried the apple usb-keyboard on a windows pc: no problem. Eventually, also tried the extension cable trick, and that made it work again. Very strange behavior indeed.

Try a PRAM Reset, sounds like the computer is confused about what equipment it is expected to see...and the PRAM reset is the same for all Mac OS X versions so don't worry about that article saying Mountain Lion.

The settings that are changed are those inconsistent with the hardware configuration, not your personal settings like email address, and so on. You need to do the PRAM reset with the USB keyboard attached so the Mac is seeing that hardware and will enter that info in the PRAM, a memory location that stores the information on the equipment being used at that time.

The PRAM reset is a pretty harmless thing to do and often clear up confusion the Mac may be experiencing. It sounds like your is confused as to what keyboard it is expected to use so the goal is to make it see the right keyboard and remember which is the right one.

Hi, There

I just bought my My I mac 27" Inch (Late 2012), Instit of Blutooth Kepyboard I prefer Wire Keboard but eveytime I start the machine some noice is come, seems like ots not aceepting Keboard becuase its stop when I plug keboard wire.

I try your suggested method but it doesnt make any difrrence.

Since you bought your machine in the past few months, if you ordered direct from Apple with the USB keyboard instead to the Bluetooth keyboard, it would be a good idea to take it to an Apple store genius bar and have the techs see why it is not accepting the keyboard. I bought an early/mid 2012 iMac with the USB keyboard direct from Apple and it works perfectly with that keyboard and the Magic Mouse. So you really need to get Apple to sort out why yours, if factory supplied with that configuration, is not working right.

It would be better to do the PRAM reset with the USB keyboard since that is the one you want the Mac to see as the primary keyboard. You could take the USB keyboard to the Apple store genius bar and have it tested to be sure there is nto a fault in the keyboard itself. If that checks out ok, then the Mac and keyboard to see why they are not communicating correctly.

You are welcome, ernesto...just sorry to not have a solution that worked. If you have time, after visiting the geniuses please post the resolution of the problem. We are all fellow users on here and not Apple employees, so how problems get resolved is helpful to know.

I am having a similar problem. My usb keyboard will not work with my iMac since the last time I turned it off and unplugged it. I have tried plugging other devices into the the USB ports, such as my iPhone and camera, and they work but my keyboard won't. I have also tried my keyboard on a different computer (an old Mac mini) and it worked! But after trying again on my iMac, still no luck. Anyone find a solution yet?

That is definitely some strange behavior, good to finally be working, but does not explain exactly what causes the behavior. Could have something to do with the energy saver part of the operating system, or a miscommunication with the USB bus itself. With multiple USB ports it would be good to test on different ports to see if that is an issue. Anyway, it is working now and that is good.

Another I don't know why but it works: a couple months ago a user was having problems with a wireless keyboard. The keyboard-iMac communication resulted in random charaters, time lag, and other bad behavior. The user finally found by accident that turning the keyboard off, removing the batteries, and then spending about five minutes just pressing keys, placing the palm of the hand on the keyboard and pressing, just pressing and pressing, and then replacing the batteries and turning on the keyboard, it worked fine. Seems like it is necessary to just force the keyboard to discharge all of the key switches. Those keyboards use capacitance switches instead of mechanical switches. So they retain a charge.

While that was a wireless keyboard, I wonder if that was what happened in a way with your keyboard...the unplugging and leaving it for a period of time, any charge may have dissipated and it would work again. If this happens again, try the above procedure and see if it helps.

You are very welcome, ernesto.