imac 2012, usb keyboard not recognized

I have had to do the USB hub fix. i should not have to fix anything! After many wasted hours. On other occasions, unplugging the keyboard works. Since I need the full keyboard for my work this actually costs me money. Apple has been aware of this problem for several years, as I discovered from a web search. This means that they have been knowingly selling kit which does not reliably fulfil its purpose. Under UK consumer protection law this is illegal. What does USA consumer protection law say? I suspect they are being foolish not fixing this problem, as a lawsuit could prove very expensive.

I have experienced the same problem. I have a fix. (not ideal) I have a windows laptop and I plug my keyboard in there. It starts to automatically install drivers for the keyboard. I unplug it back into my mac and it works again.

Fixes the problem everytime but should be better!

New 27" 5k ... When it reboots it looks for a Bluetooth keyboard, not recognizing the USB keyboard. I have a mouse plugged into the keyboard USB port. So far when I unplug the mouse and plug it back in, everything starts working again. Mine did not come with an extension cord as far as I can tell, unless it's hidden really well. I am using a non-Apple extention.

Thank you for this fix! This has been such an annoying issue on my "Late 2012" iMac. It's so odd, because it'll reboot and the keyboard will work fine for however long it is until the next reboot, regardless of any amount of jostling or messing about that I might do to jangle the connection. But then it will restart and I'll get hung up on the login screen because I can't type in my password. I can restart 10 times and it usually won't fix it. Eventually I just have to put the computer to sleep and then come back the next day and it usually has decided to work. Clearly it's working now. Off to buy an extension cable, which is frustrating, but far better than buying the bluetooth keyboard that I have in my Amazon cart to try to fix the issue.

I found this thread after having the same issue. It only started happening for me after I bought a brand-new keyboard for a 2012 iMac. When I use an older keyboard on the same iMac I don't have the problem, somehow it is related to new Apple keyboards. The only USB extension I have is 10 feet long and doesn't fix the problem. I'll get a short one and try that.

Yes using the extension USB cable fixed the problem. Thank you. Is it the USB plug on the Apple keyboard cable or the USB socket on the back of the iMac?? Apple you have a problem

Yes had the same problem but using the USB extension cable has solved the problem. Maybe this why the extension cable was in the box???

I have a 2014 Imac 5k and this happens to me also. The extension doesn't fix it and I doubt it's the connection because my ILok key that is plugged into the other usb port on my keyboard lights up. Unplugging and replugging the keyboard fix's it.

Bluetooth is off.

Thanks so much, you literally saved my life, I thought I was getting crazy with my 2 keyboards and USB graphic tablets ...

This is a ridiculous problem though, but bless you for posting this solution!

Just get something to scratch up the brass inside the end USB cable. Or you could use some ferric chloride if ya have that sitting around