I have an iMac and have used a wireless keyboard without problems. When the batteries died, I just changed them and everything was fine. Now, the green light blinks three times in succession and BlueTooth no longer recognizes my keyboard. I try to re-pair it and my old keyboard name is still in there. It gives me a KEY to type in but nowhere to type it. Eventually I get a message that the pairing was unsuccessful. I tried doing searches on how to remedy this but couldn't find anyone with any answers other than "Bluetooth isn't always reliable. Get a wired keyboard." Well, I have a USB keyboard but the cord isn't long enough. I miss the freedom of my wireless keyboard. Can anyone help? ETA: It's still under warranty, by the way. Should I just bring it back and exchange it? ETA: Also, my keyboard preference IS set to Discoverable.