I guess this pretty much sums it up.
 
I'm halfway through a project where I have already recorded midi.  I'm trying to record a second track.  The track is armed.  The instrument plays and I can hear sound.  I can see midi coming in on the meter. 
 
When I press the record button, it does not illuminate and only plays back the other tracks, I can still hear myself when I play, but it never gets recorded.  If I switch to step time, it does record.
 
If any one could suggest what could be wrong it would be much appreciated.

I could think of reasons why it wouldn't record (most common: autopunch enabled in another part of the project), but I don't recall ever hearing of the record button failing to light when there's an armed track in the project. Sounds like a driver issue of some sort. Does it happen in a new project? Have you restarted SONAR or rebooted since this came up?
 
EDIT: Actually, I just realized that autopunch would account for that. The record button will only be lit inside the punch region.
 
 

quick update.  If I start a new project it records again.  so possibly a file problem??

See the edit to my previous post.

Autopunch? where would I find that?
 
Yes rebooted and restarted project several times.  Another related thing could be that the project has been opened and edited in X1.  so it started in X2 went to X1 and now it's back in X2, could be related.

found it, yes bang on, that's what it was. Autopunch!
 
Thanks so much for your help!  :-)

there should be a Punch module in your Control Bar unless you moved it offscreen. There might be a hotkey to toggle it on and off, but I don't know it offhand. If you don't see the module, right click the Control Bar, and check Punch Module.

Too slow. Guess I need more coffee.   Glad you got it sorted.