I appreciate the post-Yes I know all of this-30 years of midi....But all I posted was to see if there was a way to see a list of used\ or unused midi channels. Nothing less and nothing more. Point is I want to see them all at once. But I cannot. Thanks for everyone who replied. I am going ahead like John suggested and make the feature request-cannot hurt
Frank

Frank one never knows where good questions will lead. I think some of the answers are not aimed at you but at others that have a limited understanding. I know I wasn't posting to you in all my responses. I know you have a thorough understanding of MIDI and Sonar.
 
Don't forget we have a lot of new users that don't have a lot of knowledge about MIDI in Sonar. Because of that its a good thing when members add information to the thread.     

Yes your right.....Just a bit touchy but for an unrelated reason- I appreciate so many folks trying to help and posting good info...

Here's a crude CAL script that will indirectly tell you which channels are used or not -- if there are 0 channel events, then that channel is unused.    Which means -- no midi events.   It's still possible there is some empty track assigned to a midi channel for input or output.     You must select all midi tracks for this to work, or you could use it only for a group of selected tracks.  
 
Copy & paste into notepad or some text editor, save it under Cakewalk Content/Sonar Platinum/Cal Scripts" -- or whereever your cal scripts live. 
 
 
;; show_channel.cal  Count Midi Channels for selected events.
;;

(do
    (include "need20.cal")    ; Require version 2.0 or higher of CAL

    (int c1 0)        ; counters
    (int c2 0)        ; counters
    (int c3 0)        ; counters
    (int c4 0)        ; counters
    (int c5 0)        ; counters
    (int c6 0)        ; counters
    (int c7 0)        ; counters
    (int c8 0)        ; counters
    (int c9 0)        ; counters
    (int c10 0)        ; counters
    (int c11 0)        ; counters
    (int c12 0)        ; counters
    (int c13 0)        ; counters
    (int c14 0)        ; counters
    (int c15 0)        ; counters
    (int c16 0)        ; counters


    (forEachEvent
        (switch Event.Chan
            0 (do
                      (+= c1 1 ) )
            1 (do
                      (+= c2 1 ) )
            2 (do
                      (+= c3 1 ) )
            3 (do
                      (+= c4 1 ) )
            4 (do
                      (+= c5 1 ) )
            5 (do
                      (+= c6 1 ) )
            6 (do
                      (+= c7 1 ) )
            7 (do
                      (+= c8 1 ) )
            8 (do
                      (+= c9 1 ) )
            9 (do
                      (+= c10 1 ) )
            10 (do
                      (+= c11 1 ) )
            11 (do
                      (+= c12 1 ) )
            12 (do
                      (+= c13 1 ) )
            13 (do
                      (+= c14 1 ) )
            14 (do
                      (+= c15 1 ) )
            15 (do
                      (+= c16 1 ) )
        )
    )
       
    (pause " Ch 1: " c1 " Ch 2: " c2 " Ch 3: " c3 " Ch 4: " c4 " events" )
    (pause " Ch 5: " c5 " Ch 6: " c6 " Ch 7: " c7 " Ch 8: " c8 " events" )
    (pause " Ch 9: " c9 " Ch 10: " c10 " Ch 11: " c11 "Ch 12: " c12 " events" )
    (pause " Ch 13: " c13 " Ch 14: " c14 " Ch 15: " c15 " Ch 16: " c16 " events" )
)


 

A probably obsolete FYI, but back in the days when 32 bits ruled the land, Midi Ox had a monitor that showed channel activity as readout of 16 LEDs (one for each channel). Also, Midi Yoke (or more recently, LoopBe1) can provide a "virtual cable." In theory, you could do a temporary QuickGroup in SONAR to send all MIDI outs to Midi Yoke, and have Midi Ox's monitor read Midi Yoke as in input so you could see instantly which channels were producing MIDI data and which weren't. It worked very well back in the day, but unfortunately I tried all this with 64-bit Windows 7, and no joy. There's also a MIDI Monitor made by someone in France, but it too is 32-bit and for whatever reason, I can't get it to work.
 
In any event LoopBe1 still provides a virtual cable that works just fine with 64-bit systems. Now all we need is some kind of MIDI monitor to read the data. It's a pretty trivial coding exercise; maybe William Copper could build on what he just contributed (THANK YOU!) and knock one out for us.

Kontakt has a midi monitor, easy to use.   Not sure about Kontakt player ... possibly not. 

Also, 'midimon' which I believe is part of midi yoke, works fine on my 64 bit system -- but getting the plumbing right can be irritating and time consuming.   The programs, again part of that (maybe?) called 'lsmidiins.exe' and 'lsmidiouts.exe' also work fine.  So for that matter do the netmidic and netmidid ('client' and 'demon') programs.