Midi I/O problem with M-Audio 4x4

Hi Guys,
I'm using my laptop mobile studio (Sonar X3 studio) at the moment with two midi controller keyboards, three outboard boxes, a Focusrite audio interface and an M-Audio 4x4 midi interface.
Sonar shows that I have correctly assigned the keyboards to midi in on the 4x4 and the outboards to midi out on the 4x4. However, although the 4x4 LEDs show midi activity on the selected inputs, there is no LED activity on the output ports - and therefore no data passed to the outboard boxes.
 
Using Midi-Ox (externally to Sonar) the keyboards inputs route correctly to the outputs and the outboard boxes sound correctly. 
 
I have therefore concluded that there must be a problem internally with Sonar software? Has anyone else had a similar problem and know of a setting I may have missed in the set-up? Or have I reached a point where I need to re-install Sonar software - which would be a right pain 'coz I'm in Spain and the software is in the UK!!!
 
Any thoughts anyone?
  
 
 

I had exactly the same problem yesterday with my Roland A-Pro keyboard. The midi LED's in the notification area registered but there was no input on the midi tracks.
 
Reinstalling the drivers didn't help. In the end I started a new project from one of the Sonar default templates and it started to work. From then on it worked in all projects. 
 
A weird one. I have noticed a few people having midi i/o issues on the forum lately though.

Yes I've been having intermittent I/O issues with my 4x4 midisport (the old green one).  I've done a little trouble shooting and was leaning towards Win10 as the culprit.  I know there was a Win 10 update just before I first noticed problems.
 
Are the most recent drivers those 2010 Win7 drivers?  I don't think I even reinstalled them when I migrated up to Win10 but it kept working fine for a good bit.  And even now it works 90% of the time but I'll get that same thing where I'm getting activity lights but it doesn't seem like the data is getting through.