Q: Wireless keyboard won't connect

This worked!  (once I figured out what you meant by the "-" button.) 

Thank you so very very much TM100. You saved the day, after two days of frustration, after one morning my wireless keyboard just decided to take an extended vacation. Wasn't looking forward to possibly lugging my heavy large iMac to the Apple Store. And thank goodness for iPad so I could search in depth for your answer, as I didn't see it the first time I looked. Always learning from other Apple users.

I tried this and my wireless keyboard still is not pairing with my MacPro (10.9). It was working last night, but not this AM. The light on the keyboard blinks, I try to "pair," I get a 6 digit number, I type it in, press return, and the keyboard light blinks some more and then goes off. I repeat numerous times and it does the same thing.

Count me in as having the same problem with 10.9 and a Mac Pro. Keyboad works fine with iPad and an iMac with 10.8 so guessing it is 10.9. Never had problems before 10.9.

No matter what was tried listed here, no luck.

I just kept trying the suggested remedies, and the next day tried again and it is back working. Go figure. Not sure what happened, but al is good now.

Thank you for this.

I too wasnt getting the + to add device with Maverick.

This worked perfect after 2 days of tyring to get my keyboard working again.

Thanks so much.

Thanks @SweetMummy!  Holding the power button worked for me as well.  I'm using Mavericks by the way.  

SweetMummy:  thanks for your detailed and patient explanation.  The only thing that worked to get my wireless Apple keyboard recognized by, and talking to, Bluetooth.  This with a mid-2010 aluminum keyboard connected only to an iMac, upgraded to Mavericks about 6 weeks ago.  Still don't understand what the problem was, but after several days of futzing around, switching batteries, buying new batteries, trying the aluminum foil thing, multiple reboots, System and Bluetooth Preferences operations, and untold online forums...I'm back in business!

Hard to believe I had to hold in the power key the whole time, even while typing in the passcode, but there you go.  Nobody ever said computers had to behave logically.  Oh, wait...

.....and here's how I solved my problem.  Tried removing the batteries many times, but the keyboard just would NOT enter pairing mode.  Left batteries out for an hour - still would not go into the "flashing" setup mode.

Read every available article on the subject......then in desperation I took the keyboard outside my house and walked until there could be nothing within Bluetooth range (not even my mobile phone).  I then pushed the ON button and held it for 5 secs.  Bingo - it started to flash, so I ran back to my Macbook and I got the pairing code immediately.

Thank you.  Your solution solved my keyboard problem.

Great! But how on earth do you get passed the login screen to do this??? :C

I am trying to delete the keyboard but the '-' symbol is unavailable and it's telling me the keyboard is still connected even without the batteries in it and it won't let me disconnect. Is this a glitch??

Yes I have a USB keyboard now and have restarted the machine but it still says the keyboard is connected. Il check my other devices to see if the keyboard is somehow connected to them by accident. Thanks anyway.

THANK YOU!  Worked like a charm for Mavericks and saved me another 30 mins frustration!