Please can you give an update Cakewalk. You are advertising xmas holiday bundles, but all I want for xmas is a stable system back. I now cannot have clients here, due to crash after crash. Please update me so I can update my clients. 
 
Appreciated.
 

Agreed! I've been in contact with email customer support and they were also unable to provide any details or a timeline for a fix. I just bought a few Native Instrument libraries for Kontakt that I've been unable to use since this issue. Please give us an update!

Win 7 is showing signs too. Sonar is very sluggish and slow, and has crashed a couple of times.

 
Review this post and look at Bitflippers comment to use Process Monitor.:
http://forum.cakewalk.com/Instability-with-certain-Cakewalk-plugins-after-recent-Windows-10-updates-m3526221.aspx
 
All Process Monitor does is show running Processes.  It is available here and once I started using it with SONAR, my instabilities stopped.  Just start Process Monitor up, and then SONAR.
 
FYI Process Monitor is a Microsoft application available here:
https://technet.microsoft.com/en-US/sysinternals/processmonitor.aspx
 
While not the end all solution, it IS a solution for now...
 
Best of luck and keep us posted if you do try this.
 
Thanks,
Pat.

patm300e
 
Review this post and look at Bitflippers comment to use Process Monitor.:
http://forum.cakewalk.com/Instability-with-certain-Cakewalk-plugins-after-recent-Windows-10-updates-m3526221.aspx
 
All Process Monitor does is show running Processes.  It is available here and once I started using it with SONAR, my instabilities stopped.  Just start Process Monitor up, and then SONAR.
 
FYI Process Monitor is a Microsoft application available here:
https://technet.microsoft.com/en-US/sysinternals/processmonitor.aspx
 
While not the end all solution, it IS a solution for now...

+1. Running long sessions at the moment by starting Procmon whenever opening a project or inserting one of the noted problem VSTs. I had been stopping it once a project was open and running (for no great reason) but noted a few other flaky issues never seen before. (a "General error" dialog when sometimes trying to close a project, some display issues with older projects, an occasional transport lock-up). Probably more robust to leave it running. 
 
fwiw, NO any issues with any other VSTs (including UAD, Nomad Factory BT, BlueCat, Melda, BFD, AAS, Synthogy, NI, etc.) 
 
NB. Survived the latest (Dec) Win10 update with no apparent change in operating status.

The easiest workaround is to start SONAR and close it. For me, at least, the problems do not reoccur after SONAR has been opened once. They reappear after a reboot, however.
 
It would be nice if Noel would give us a little information, though. I'm sure he already knows what the problem is, but the fix is likely going to be very difficult. I'm also sure he's deep into it and hasn't seen a 40-hour workweek since this all began.

bitflipper
The easiest workaround is to start SONAR and close it. For me, at least, the problems do not reoccur after SONAR has been opened once. They reappear after a reboot, however.
 
It would be nice if Noel would give us a little information, though. I'm sure he already knows what the problem is, but the fix is likely going to be very difficult. I'm also sure he's deep into it and hasn't seen a 40-hour workweek since this all began.

"That seems to work here as well, at least for a couple of hours."
 
<update>
No go today. Started Sonar, closed, restarted and back to "SONARPLT.exe has stopped working." when trying to open a project.
 
I've blown my budget for troubleshooting, Getting by -on my PC- by running Procmon when opening/closing a project or inserting one of the problem VSTs, which I avoid as much as possible.  
 
hth   (!= hacking the holidays...)
 
 

An other solution that I found is to run first  Sonar X3. Then open the project that cause SPLAT to crash in X3. X3 will handle it flawlessly. Close the X3. Then open the project with SPLAT and everything will run smoothly..no crash..no pain.. 

Do you save the project in X3 before closing it?

bitflipper
The easiest workaround is to start SONAR and close it. For me, at least, the problems do not reoccur after SONAR has been opened once. They reappear after a reboot, however.
 
It would be nice if Noel would give us a little information, though. I'm sure he already knows what the problem is, but the fix is likely going to be very difficult. I'm also sure he's deep into it and hasn't seen a 40-hour workweek since this all began.

Yep, agreed. I generally have to start a project first though. Closing and restarting before doing this will still get me a stop working. Usually - with a couple of exceptions - projects fire up after that 1st stop working issue and continue to perform well for long sessions. 
 
This issue occurred after the Nov update and before any Win 10 update. These latter updates came after the Nov update. 
 
I'm was hoping for a fix before moving forward with any early access update, which from what I've seen, doesn't seem to fix what's going on with this issue.