I downloaded the Dorchester updates and now I keep getting a message that Sonar wants to set itself as the default .mid player.  I do not want Sonar as the default.  I have Windows Media Player set as default for .mid files. 
 
I keep denying the change but it keeps popping up. (I have BillP Studio's "WinPatrol" program that monitors all changes and alerts me).
 
The Sonar file that is trying to change the default .mid device is:
"SONARPLT.exe %1"
 
How do I delete Sonar's intrusion?  I hate ill behaving programs that try to set themselves to do something. 
 
 
 Well, I fixed it.  I rolled back to the previous version and then rebooted the PC.  No .mid request from Sonar.  I then reinstalled the Dorchester update.  NO .mid requests.   However, I had to do this on both Win 7 and Win 8.1
 

I installed the Dorchester update in my Win 8.1 system, to see if it was a Win 7 issue but its not.  It does the same thing in Win 8.1 so its definitely a Sonar problem. 
 
I have opened a problem report to Cakewalk. CWBRN-32777

fireberd
I installed the Dorchester update in my Win 8.1 system, to see if it was a Win 7 issue but its not.  It does the same thing in Win 8.1 so its definitely a Sonar problem. 
 
I have opened a problem report to Cakewalk. CWBRN-32777

For now you should be able to select a midi file and right mouse and then select "open with" and then "choose default program" this should reapply the application you want midi to open with as the default. 

I don't have a problem with association.  I just deny the change with Win Patrol and it remains my choice.  However, the program is still trying to change it and I get popups from Win Patrol that Sonar is trying to change it.
 
Unless you have a program such as Win Patrol that monitors for any changes and notifies of the change request, you probably would not know its happening.  Or if the PC is only used for Sonar and nothing else it wouldn't make a difference.
 
This has only started with the Dorchester update.  I've had Sonar since Version 7 and it has never happened before.
 

Quick clarification on the above... you are saying that SONAR itself is trying to create file associations each time it loads? Or just during the installation of the Dorchester update?

Is it possible that WinPatrol is just reporting that Sonar is registering itself as a .mid player? On my win 8.1 system wmp was associated with .mid before the update and it's still associated after the update. In other words on my system Sonar didn't change the file type association but just registered with windows that it can open .mid files.

The message I've getting from Win Patrol is that it is trying to change the default from Windows Media Player to Sonar. 
 
Sonar does not have to be running, I get pop ups from Win Patrol every couple of minutes that it is trying to change.

Based on Steve's post (above yours) it may be a false alarm.  Is there a way (in Win Patrol) not to report that?  Surely if it's that incessant, there should be some sort of customize function to "turn it off".

The Sonar Platinum.exe program is the one that is requesting it.  Win Patrol monitors for any system changes, such as a file type association and reports when another application is attempting to make a change.  And as I have previously posted if you do not have a program that monitors such as Win Patrol you wouldn't know it has happened, unless you had .mid set for some other program and checked the file associations.
 
As I noted I have not had this in prior Sonar Versions (since V7) and ONLY since the Dorchester update.  It is happening in both Windows 7 and Windows 8.1.

fireberd
....  And as I have previously posted if you do not have a program that monitors such as Win Patrol you wouldn't know it has happened, unless you had .mid set for some other program and checked the file associations.
 
As I noted I have not had this in prior Sonar Versions (since V7) and ONLY since the Dorchester update.  It is happening in both Windows 7 and Windows 8.1.

Did you not see the post above yours saying that he installed the Dorchester update and it did not change the file association?  He doesn't need Win Patrol to verify that.
 
Have you actually checked to see if the file association has changed?  (You may need to "allow" the change).  It could still be a false alarm.