*wall of text ahead* About this time last year, I noticed a very odd problem began to occur in my iMac; at startup, my Magic Trackpad and Apple Wireless Keyboard would not instantly turn on (as indicated by the green power lights). The times varied (with sometimes being instant, or close to it, and sometimes a full minute or so), but often took 5-30 seconds. So, I delved into various troubleshooting attempts: - turned Bluetooth on/off - deleted Bluetooth and peripheral plist files - added peripherals as favorites - changing the batteries - re-paired the devices - changed the batteries - reset SMC and PRAM - restored to earlier Time Machine backup - standard reinstall of Snow Leopard After doing all that to no avail, I turned to the Genius Bar. They used different trackpads and keyboards and booted from an external hard drive to come to the conclusion that it was a hardware problem, that the Bluetooth chip was defective. So, they replaced it. It seemed to work for a day or two, then the issue came back again. I ignored it and installed Lion not long after, and the problem, while not eliminated, was improved after that (though, I did notice that it would be a little worse after every 10.7.x update, but would get better in time). Flash forward to now, Mountain Lion, and after doing an upgrade install, the problem was still there. Due to other problems with ML, I decided to do a clean install of it, hoping it would solve all of my problems, this included. But lo and behold, the issue was still there. So, I went to the Genius Bar again last week only to get a call a day later saying they couldn't reproduce the problem (though I'd rather see it with my own eyes, as they didn't even turn on the machine when I took it in), and that it was very possible that there was interference causing the problem. The only thing I could imagine causing interference is my old 802.11g router, as I have no other Bluetooth products in my house besides the keyboard/trackpad. Google results seemed to indicate that Bluetooth and 802.11g can conflict with eachother, but not with a 802.11n router. I don't have an N router, so I decided to go to my parents' house where there is one (and also nothing else that would seemingly cause interference), and the problem persists. While there, I changed the wireless channel from Auto to 11 and booted into safe mode, yielding no results. I'm at a dead end here. I've tried everything I can possibly think of, and the Genius Bar can't even help. Hell, most people can't either, considering I've reposted this problem multiple times on various message boards in the past year and pretty much no one has replied. It's an annoying problem, and I'm hoping someone else is experiencing it and/or can help solve it.