PS For some reason protection was turned off on my Sweetwater PC so there are no restore points to allow me to back out the EZ D 2 installation. GRRR

POSSIBLE SOLUTION:
 
I closed Sonar and opened EZ Drummer 2 in stand-alone mode.  In Settings I saw that audio was set to MME.  I changed this to ASIO and closed EZ Drummer 2.  Then I opened one of the corrupted Sonar projects and it played without problems.
 
I don't know if this is a 100% solution, but you should take a look.

I observed something yesterday that might be a clue to what is going on.  I opened an old project that used OrgaNized Trio for the softsynth on an Organ track.  I have a new computer at this time when I opened the project and OrgaNized Trio wasn't installed so I downloaded the software and installed it.
 
I expected the new Organized Trio to simply take the place of the old version in the project but that wasn't the case.  I opened the synth rack and deleted the old grayed out, inactive version of OT but I selected the option to not delete the associated tracks in the project.  When Organized Trio synth was deleted, I discovered that the output of True Pianos had now been assigned to the original Organ playback tracks.  Sort of like musical chairs.

Now the question is, how does a soft synth take over the outputs or inputs of a track in SONAR?  A soft synth has no way to take over anything in the way I am thinking.  I would expect the old OT tracks to have "none" or something to that effect assigned as place holders until a new softsynth was routed to those inputs or outputs.
 
How does this relate to EZdrummer 2 and the SONAR I/O issue?  I don't know how the inner workings of these two programs operate but I suspect that if a softsynth shows up with the same identification as an old version but it brings more outputs to the party that the host expects from it (based on some sort of project or global data it has stored), it might just be confusing the host into acting somewhat like what I observed in my opening paragraphs.  So now instead of adding 16 chairs at the dining table for the unexpected guests, some folks lose their place.

Toontrack knows about the problem and Cakewalk knows about the problem and that was confirmed by CW staff.  I've got a feeling (and no hard knowledge) that there will have to be some sort of solution worked out by both parties because under the same conditions, I have only been able to reproduce the mis-routing of I/O between EZD2 and a legacy project in SONAR.  I have two other competing products with legacy projects using EZD1 that have no problems with EZD2.   So you can alternate even and odd days at who to be upset with, IMHO.

Bottom line, be patient and it will get fixed.  

Mod Bod, Did you see my separate post about changing the audio setting in stand-alone mode?  Although I have had to reroute a few things, the other bizarre problems have gone away (at least so far....)
 
OK , PARTIAL RETRACTION.  Now when I freeze synths, sometimes a lot of notes or parts are missing.  Example: freeze the drums and the toms aren't there, or freeze RealGuitar and some sections of the song are missing.  I have had this problem before EZ 2 but not as frequently or as severe.  So, not sure if I'm OK or not.

konradh
Mod Bod, Did you see my separate post about changing the audio setting in stand-alone mode?  Although I have had to reroute a few things, the other bizarre problems have gone away (at least so far....)
 
OK , PARTIAL RETRACTION.  Now when I freeze synths, sometimes a lot of notes or parts are missing.  Example: freeze the drums and the toms aren't there, or freeze RealGuitar and some sections of the song are missing.  I have had this problem before EZ 2 but not as frequently or as severe.  So, not sure if I'm OK or not.

Yes, I saw that but I've used ASIO in my standalone version since I received the first beta so if that is a factor some way, I'd be surprised.  I wish I had run across the issue then but I had to hunt through old projects recently to find one that still had EZdrummer in it.  Since there wasn't any advantage to building a midi performance in EZdrummer, I usually swapped out EZdrummer for Superior Drummer somewhere early after a track was fleshed out and getting into the mixing stage.  So I have mostly Superior Drummer projects from when I used SONAR.

As far as missing sections from various softsyths are concerned, I think that you either have a seriously afflicted system (your system specs look good but I don't know the health of your software installations) or your abundance of sampled based instruments is causing you problems.
 

I may have spoken too soon because my audio is still intermittently screwed up.  At this moment I can't get any audio from Sonar.  Now the standalone EZ 2 won't let me pick an output device.
 
Regarding the freezing of soft synths, I hear you, but I am talking about projects that were completely fine until the EZ 2 installation.  It has seriously screwed me up.

Crash in Sonar X3e - first one for a long time.
 
In a new project using EZdrummer2, first noticed that clicking notes in PRV produced no sound from EZd2.  Clicking on GUI, or triggering from controller produced no sound either.  SIT track f EZd2 still played back okay.
 
Tried to close Sonar and CRASH...
 
Luckily it sent a Crash dump.
 
CWBRN-26108 - shown as reproducible.
 
Since contacting Cake wit EZdrummer2 issues, they have been their usual excellent selves.  Ryan responding on here and keeping in contact, explaining what they're doing.
 
After my initial Email from Toontrack, saying that they did not understand my problem, I have heard NOTHING AT ALL.  Even to acknowledge the further info that I sent when they asked.  I know that they must be busy with the new release, but surely this is part of the new release cycle..
 
Last time I needed assistance from Toontrack, I ended up contacting their distributer here in U.K. (Time&Space) who chased them up .  I got a rapid response then.
 
@Konrad - perhaps try something like that..  I may have to do the same now..

Any updates on this issue?
 
Thx.

http://forum.cakewalk.com/FindPost/3044739
 

Glyn Barnes
http://forum.cakewalk.com/FindPost/3044739
 

 
The update has not fixed this issue at all.