Who knew? I've been having a problem for almost a year now with my Korg X50 -- my Windows machines won't see it, no matter what I do. My previous attempts to sort this out (with or without the help of Korg tech support) have been fruitless. A couple of days ago, I opened up a new support request with Korg, and this time I seem to have found a support engineer who might be able to get me going!
I'm trying to get this to work using my Acer laptop instead of the MacBook (everything works great on the Mac, of course), which has four USB ports. I'm connecting a Tascam US-1641 USB audio/MIDI interface on one, and the other three ports are reserved for the X50, a Korg PS60 and an M-Audio Radium 61 controller. In order to make for quick setups at shows, I went through and connected every device to every port. But, as it turns out, every time you plug a USB device into a different port, a new copy of the driver is installed. And Windows supports only ten MIDI devices. A quick calculation shows that 4 ports times 4 devices is 16 MIDI driver loads. Ooops.
Fortunately, there is a fix. This article in EQ Magazine (TECH BENCH Fixing Windows XP MIDI Port Problems) by Craig Anderton explains how to fix the problem, once you've created it for yourself.
So, at this point, my thought is to wipe out all the MIDI driver information and start over. And then ONLY plug each device into a single USB port. I won't get to try this out until Sunday, so stay tuned. I'll update my progress then...
Update April 1, 2011: I had a little bit of spare time between work and the concert I was going to last night, so I dug into this a little. It took a little bit of time, but the end result is that the Acer laptop now sees both the X50 and the PS60, as well as the Tascam US-1641 interface. One thing to note -- if you're running Windows7, and your MIDI devices use WDM drivers, all of the MIDI entries in the registry will point to the 'wdmaud' driver. Just go ahead and delete all of the MIDI ports in the registry and start over. Much less headache that way.