I just got a new 2012 Mac mini last week. I plugged in the power cord, ethernet, and my old VGA monitor via an Apple mini display port to VGA adapter. When I turned on the power, the Mac played the startup sound (bong), then played it again, and again, and again, etc. The monitor was in standby mode and never turned on. I called AppleCare and did all the standard stuff with them. They recommended I exchange the mDP to VGA adapter. I exchanged the adapter and tried again with no change in behavior. When the adapter/monitor is unplugged, the MM plays the startup sound only once, and is assumed to be booting okay. I called AppleCare again, and recommended exchanging the Mac mini. Being a CTO, this took some time. I got the brand new replacement MM today and tried again. Exactly the same behavior. I called AppleCare again and went through the process again. They don't have any great solutions for me. It appears to be a compatibility problem. The monitor works just fine with my old Mac Pro that I still use. I have found that I can use the power button on the monitor to actually power off the monitor -- not standby. With the monitor powered off, I can then turn on the MM and it appears to boot just fine. If I wait a sufficient time for the MM to boot, I can then turn on the monitor and it will come alive and work just fine. Using this procedure, I have been able to so far use the MM normally with no problems. But, I cannot restart the MM or the looping startup sound will occur. As long as the MM is started with the monitor actually powered off, it works. Ultimately, I'm wondering if anyone has had a similar problem? I have also found that if I use my HDMI TV as the display, the MM will play the startup sound 2 times and then continue normally. Although this isn't as bad a problem, it is definitely not the intended behavior. I also am not using my TV as my monitor and only tried this as a test.