today must be the day of midi sticking notes. i'm using the Roland Fantom G6 with Sonar X3 Studio and I've had the same problem since last week and just like the other user I've increased buffer size, I'm using midi cables not USB and my interface  is a M-audio fast track pro. And yes your right if you press the reset MIDI button in the transport bar it stops. it almost seems like there's to much midi happening at the same time so, is it the interface or Sonar? is there another way to break it down? as far as the input echo goes I've had them on and off still the same problem. Any more help would be great.

Yup, MidiSports have a long checkered history. Check with M-Audio to see if there are updates available, not only for the Windows driver but also for the unit's firmware, which is upgradable.
 
This wouldn't explain 88fingers' problem, though, unless there is some common problem between the two M-Audio products. Not an M-Audio user here, so I can't testify one way or the other. BTW, you'll see reports of stuck MIDI notes in conjunction with all interface manufacturers, even the ones generally considered a cut above M-Audio, as well as on all DAWs, both PC and Mac. It's a widespread problem, has been for years, and may come down to the fact that MIDI is, at its core, a very slow medium that can be prone to buffer overruns.
 
You're not by any chance using a USB hub, are you? Or recording to a USB-connected external drive?
 

thanks for the quick response. I check all my equipment for updates every month for the latest in updates and firmware so I'm pretty sure I'm OK in that dept. I will be sending M- audio a description of the problem and see if they have heard of the same thing. as far as using a USB I'm only using Midi cables from the keyboard to the interface. (in, out)

I also sent a note to M -Audio, and hope to hear from them soon. I even sent a link from this discussion, with an
explanation, to the Roland support staff. However, as I think of this, I'm not quite sold that the problem lies with the interface. I have several other synths, such as a Triton, Kronos, Roland XP30 and JV 880 synths, as well as a Yamaha Motif. I just don't see problems like this with any of these other synths. ANd that's with using the same interface and software. I do remember occasionally getting  some sticking of a sound with one of the other synths, but it was pretty rare. With what I believe is some association between Roland and Cakewalk, I would think they would be a little more motivated to try to figure this one out. For instance, I think when I have gotten some sticking on, ie, my Triton, all I had to do was switch to another preset, and the sticking went away. As I have said, when the sticky note starts on my Integra-7, that note continues to sustain no matter what preset I choose. Only powering off and on fixes the problem.
Thanks for listening and contributing.
LNOvik

LNovik
With what I believe is some association between Roland and Cakewalk, I would think they would be a little more motivated to try to figure this one out.

There is no longer any relationship between Roland and Cakewalk. Roland sold Cakewalk to Gibson last year.

Thank you Mr Novik for the input.  I spoke with a Cakewalk tech in Boston today and he asked me to try a few things. this is what he said to try.
Open the Preferences > Audio – Playback and Recording to uncheck the "Always Stream Audio Through FX" box. Click [Apply] then [Close] to return to your project.
Try increasing the MIDI buffer in the Preferences > MIDI – Playback and Recording up to 2000ms.
Solo one of your MIDI tracks to see if playing only one at a time results in stuck notes or not.
Now I did mention to him that I never had this problem when using Sonar LE.
so with that said, here goes nothing. By the way, I tried the Roland interga 7 two weeks ago, "what a machine" love it!!!!!

Just one thing that I somehow remember from the distant past. 
Overlaping the same note was always a bad move. 
Back then I was in the habit of making sure every notes duration was just shy of the next.
I still sort of do that.
I notice if I edit a downloaded file they are real sloppy in this department. I was just working on a drum track where every snare hit was a stack of 3 notes on top of each other?? I'm not even sure how or why you would do this. It does make them louder which is why I found them. So I was thinking that a midi loop back while recording might cause this, So make sure you do not have this going on as it would also cause stuck notes in the loop.
Never have the track output aimed back at the keyboard your using for input.
 

I have several other synths, such as a Triton, Kronos, Roland XP30 and JV 880 synths, as well as a Yamaha Motif. I just don't see problems like this with any of these other synths.

 
Just some anecdotal information: I've had more problems with sticking notes using synths / MIDI controllers that feature true note-off messages [8nH with a release velocity component].  I've compared them side-by-side with 9nH v=0 note off messages in the same projects, but without experiencing the same stuck note problems.
 
This stretches back to at least Sonar 3.x and Project5, if not before.  Having not researched your synths' MIDI Implementation Charts, I don't know if any of this applies.  I'm throwing it out there as another potential explanation.

Re: the 88fingers post: though I don't have--on my Sonar Producer 8.5 ver---a "Preferences" heading, I did try a few things out. I chose: Options\AUdio\Advanced. This took me to a page, but there was no box that read "Always stream audio thru Fx". All I saw were a few boxes, where I had chosen ASIO and Triangular. I also saw something that said "MMCSS (Windows Vista)." This was checked, so, because I don't have  Windows Vista, I decided to uncheck it. ALso checked was "Use multiprocessor engine," which I left checked. Thus, I just couldn't find this box that you wanted me to uncheck. 
 
Then, re: the 2nd thing you suggested. Again, no preferences, so I looked for it under : Option\Global\MIDI. I did not have a heading called Playback and Recording, but each was listed separately. Under the "Playback" option, I chose "Prepare using..." It had been 250, and I increased it to 2000.
I played for about 5 minutes, and it sounded OK, but the sticking usually doesn't occur until about 1/2 hour of playing. Incidentally, while looking at all of these boxes, I was thinking that perhaps I have checked some of the wrong boxes elsewhere. I 'm not even sure I should be using ASIO. (Isn't that a song by Steely Dan?) Is there a link anywhere with rec's for all of the choices under "Options" that I might go to to make sure my other boxes are checked appropriately?
Thanks
LNovik
 

Somehow I think a MIDI buffer of 2000 will cause trouble, Most set this from 500-800. 
 
I use almost all of Sonars defaults that it chose it's self when I installed it. 
It seems to have a way to choose the proper parameters and for the most part they have always worked for me. 
I did change my MIDI buffer to 500 even though I was having no problems. 
 
ASIO is the preferred driver mode by 90% of DAW users.
But as said, ASIO is an Audio driver, not sure it has anything to do with MIDI. I think windows uses generic drivers for midi.