JCody
I was just looking for the checkbox "use per-project folders" and can't find it. Anyone know where it is?

The preference setting was removed. The feature now depends on how projects are created/saved. The cleanest way is never use CTRL+N or the "On Startup load Default Template" setting in Preferences > File > Advanced. If you do, make sure to check the "Copy all audio with project" in the "Save As" dialog when initially saving the project and also specify a new folder in the Project Path entry.

Anderton
Yes, but it's not created automatically nor can there be association with specific projects. I wouldn't encourage anyone to avoid using per-project folders, it really makes life so much easier. 

I believe it follows the rules just like per-project folders. At least does on my machine.
 
If the folder does not exist when opening a project in "Project Folder" directory, MixScenes is created in the "Project Folder" directory. If Mix Scenes are not saved the folder is removed. If the MixScenes folder is populated, it remains.
 
MixScenes files names use the project name as part of the scene name. To the extent project files are unique in the "Project Folder" directory, there are no clashes in the MixScenes folder either.
 
That said, I agree per-project folders are a better way to go.

It works when I follow the above directions. I guess its hard to teach an old dog new tricks. I've got a template that loads when I start Sonar. I'll need to figure out how to make a template that works with mix recall.

Oh My, 
 
If you don't use Mix Recall when recording, then you are missing out on a GREAT feature of the software.   I have been using Mix Recall Since it came out a feature and I have been in love with it ever since. 
 
I can't mix a project with out it.
 
SONAR MIX RECALL   Watch the video

I'm going to have to guess that my issue is the project in question was started in X3 and then moved to splat.
It has been saved a few trimes since I attempted to create a few mix scenes.
I just opened it again and attempted to create an other mix scene and it wants to call it Mix 7 so it is remembering that I've tried to use it but on closing the project there is no Mix Scenes folder and menu is still greyed out in ways that make recalling, renaming or deleting unavailabe.
 
So I'm gonna call this one solved for me.
Thanks for talking about it.

Hmm...not sure it sounds "solved" to me, or you'd be able to use Mix Recall. What happens if you create a per-project folder, create a MixScenes folder inside it, open the project, and save a Mix Scene? Next, make a change in the automation, save another Mix Scene, then save the project. What happens?

With this particular project nothing.

I tried it on a newly created project and it works.
No need to manually create the Mix Scene folder. Sonar does that.

That's why I'm concluding that it doesn't necessarily work on projects created in previous versions that didn't have Mix Scenes.

Have you tried using SAVE As on the older project and then try mix scenes. Are the older project folders in the same folder as the projects that works?

Yes ... I always version up every session like SongName_1a.cwp 1b, 1c, 2g, 5x etc.
I've saved atleast 4 versions since I started this thread.

The one that works is in its own project folder.
 

Are you saying the one that does not work is not using a per-project audio folder?
When I was asking about the folder location of the project that does not work, I mean is it in the same path as the working project. I would expect them to be in separate folders.