Intensity Extreme not always detected on iMac

Hi, I’ve been using an Intensity Extreme for some months now on my current gen iMac. Generally everything’s fine when using it but there’s one thing that’s annoying: Every second or third time I power up the iMac the Extreme is not detected. The white light is on, but it doesn’t show up in the Pref Pane or in Media Express. Also it’s not showing up in the System Profiler of OS X. I need to reconnect the thunderbolt cable either on the iMac or the Extreme and it will appear in the Profiler seconds later. As soon as it has been detected the Extreme works totally fine, there are no issues whatsoever. I can even restart OS X and it will still work. But next time I power the iMac down and then up again it’s a gamble whether it will still work or not. What’s interesting: When switching the iMac on, the Extreme’s fan will turn on for a second or two. Then I know it will work. When I switch the iMac on and the Extreme stays silent, it has not been detected. Is it probably not getting enough power?

I’m running the latest version of OS X with all thunderbolt and other updates installed and the latest BM software but is has always been the same with previous versions of both OS X and BM software. Also it doesn’t matter which thunderbolt port on the iMac I use. And I did a NVRAM and SMC reset.

It’s certainly not the biggest problem in the world, but still kinda annoying. Could this be a software issue on OS X or a thunderbolt bug? Or an actual hardware error on the Extreme or the iMac? Any help fixing it is much appreciated!

Fabian