Its been ages since I had an issue and my system still records many audio tracks without dropouts. I noticed the lights on my M-Audio UNO(USB) seem to have a constant flashing on Midi In as soon as any device is hooked into it. I have tried two different midi controllers and the usual software things like increasing buffers/latency/reboot all etc. Any ideas besides replacing the MIDI interface?
Sonar 7 Producer

Ensure you have the latest drivers for the Uno and your OS.
What synth are you using to hear the MIDI?

Yeah the drivers have remained the same and the DAW is NOT hooked to the internet so nothing has changed with the OS or the drivers in a couple of years. Midi has always worked fine and whether I use my Studiologic or Kurzweil or Korg it hooks up and transmits fine but when I press record I get just a couple of seconds in before it drops out and freezes. Since nothing software-wise has changed in years I am assuming that some hardware has gone bad. And like I mentioned the Midi In light on the UNO is flashing non-stop the minute its plugged in. I guess I was just looking for something else to try before I just buy a new interface....
 

The MIDI light flashing is not a problem. Some synths send a signal continuously. My Studiologic 88 does. 
 
Check the M-Audio control panel to see if you have that set correctly and check the MIDI Device settings in Sonar. 

Hey, Dave, good to see you back in the old neighborhood again. Don't be such a stranger!
 
Alan, if you're still there, Dave's probably right about the constant flashing indicator - unless it's because the USB port is constantly interrupting. Do you have the ability to connect the controller via DIN connectors rather than USB? IOW, does it have a round 5-pin connector on the back?
 
Don't replace the MIDI interface, it's probably not the problem. 

Did you by chance change usb ports ? 
 
YA and Hi Dave,, I thought this was an old thread when I saw your mugg.. glad to see your still out and about... PS you havn't missed much  :>