in version 6pe, i have a particular song, 
where the stop bar has just quit working.
 
will not start the song, will not stop the song.
 
if i use the mouse and hit the screen buttons, works fine..
 
if i open up any other project,
and hit spacebar,
it stops the song, or starts it, just like it always has.
 
 
should i call a priest?
 

I actually had this happen repeatedly in SPlat when I was doing a buttload of crossfades on multiple tracks for a drum correction thing. It was like every so often if I slip edited the start of the next clip "too far" (and by too far I mean some seemingly arbitrary amount) into the previous clip the spacebar stopped working. Actually I think transport refused to start altogether no matter what I did so I guess that's different than your issue.
 
When it would happen I would have to undo a bunch of the previous actions until it undid the crossfade that was making Sonar angry or simply scrap the session and go back to a previous version.
 
We're talkin' hundreds of splits, moves, crops and fades so losing even a few minutes of work was really annoying and I had to keep testing playback to make sure it hadn't started happening again.
 
No idea WTH that was about and yes it did feel like the project needed an exorcism.
 
Likely not related but it's so bizarre and random perhaps it is. Doing a lot of X-Fades and/or grouped multi track editing?

This happened to me until I realized my wireless keyboard batteries were on their way out. I guess the space bar was the first indicator that there was a problem as I use the mouse or control surface for everything else.

Batt, are you seriously still using 6?? I do support this to a point, But 8.5 was the best of the retro Sonar's. 
6 was a little buggy for me. 
I still have 8.5 on my old XP laptop and it is still my all time favourite. 
You get used to the new versions over time, I still curse them daily, but I'm always a glutton for punishment when it comes to studio gear and learning curves. I basically learn nothing other than how to make the new version behave like the old one.......
Anyhow you certainly get your mileage out of the software as your tracks are some of the best I've listened to on the song forum. Proof that software is the least important part of a great DAW recording.. 

Yes, been there done that... my spacebar stops working all the time... that is, while I am mixing.  A save clears the buffer out and the space bar should start working again.  I think it has something to do with LARGE UNDO buffers... not sure but this is still an issue 10 year after I first came across this.
 
(CNTL S) is a quick save and I find my workflow is edit/mix, CNTL S and then back to edit/mix, CNTL S.
 
This has the added benefit of a system hangup doesn't cause me to lose to much work.  Try it.
 
Jim

Cactus Music
Batt, are you seriously still using 6?? I do support this to a point, But 8.5 was the best of the retro Sonar's. 
6 was a little buggy for me. 

 
HEHEH,
 
dude, i've done two complete albums with this setup.
no problems so far.
 
which makes me think folks are too quick to drink of the koolaid, eh?!
 
LOL
i'm sure cakewalk / gibson LOVES it!
 
but, yes, i see your point,
i'm in the process of slowly upgrading my DAW, will go to the most current version of sonar once that's done.
it's gonna be a big upgrade.
 
 
but hey, 6PE works perfectly fine for me, and my product is stellar.
 
 

well, i tried the couple of things you guys suggested...
to no avail.
i even rebooted the system,
no difference.
 
finally, i simply unplugged the keyboard (it was working FINE in any other program).......
 
and that did it.
 
WTF
 

This may not be the issue in your case, but when I run into this problem I now double check to make sure the SONAR main window has focus.  Often, if I'm in some other window like a synth or a reverb and I try to start or stop playback with the spacebar, nothing happens because the main SONAR window doesn't have current focus, it can't see the spacebar keypress.  If I then e.g., mouse click on the SONAR Play or Stop buttons, that works since doing that simultaneously claims focus on the window and performs the start/stop action.  Having done that, a subsequent spacebar would then operate the transport as expected since the main SONAR window is now in focus.
 
If I reach for the MCU transport controls when the spacebar doesn't work, the MCU start/stop command works but I'll still have the problem of subsequent spacebar transport starts/stops not working since the MCU transport action doesn't change the GUI-keyboard/mouse focus.
 
Obviously, other VSTs/DLLs need the keyboard/mouse for their own functions but for me it's easy to forget that the display is not all SONAR all the time.
 
If this is not relevant or helpful, please just ignore me...  Good luck.

batsbrew
well, i tried the couple of things you guys suggested...
to no avail.
i even rebooted the system,
no difference.
 
finally, i simply unplugged the keyboard (it was working FINE in any other program).......
 
and that did it.
 
WTF
 

Is your keyboard as old as Sonar 6?  Maybe it's worn out 

hehe..
 
like i said,
works FINE, with any other program.
 
this DAW i had custom built in 2010......