I'm experimenting with an 500GB SDD for project files, separate from the 250GB SSD I use for my OS (Windows 10 x64).  I copied a project, complete with all the audio, from an internal spinning hard drive to the SSD, then opened the project from the SSD.  The audio files are still streaming from the internal spinning hard drive, not the SSD.  I'd like to keep the files on both the SSD and the spinning drive as redundant backups.  I also tried copying a video file from a spinning drive to the SSD, and Windows still accesses the spinning drive instead of the SSD, even though I open the file from the SSD.  So it looks like a Windows issue, not a Sonar issue.  Can anyone help me get the files to stream from the SSD?  Thanks.

Hi. Do a save as, and select copy all files with it to the new SSD. Delete old files when done and sure all is well.
All the best.

You need to change the folder location inside Sonar. Edit -> Preferences -> File -> Folder Locations -> Project Files.
 
Copy your Cakewalk Projects folder from your system drive to your secondary drive and then change the folder location inside Sonar. 

I changed the folder locations in the preferences section of Sonar, and it is still streaming the audio files from the spinning drive.  I was hoping to keep the files on the spinning drive as an easy backup without using an external backup drive, but as long as the files are present on the internal spinning drive, that's where they stream from instead of from the SSD.  I did a "save as" of the entire project including audio to the SSD, but it still won't stream the audio from the SSD, even when I re-launch Sonar and make certain I am opening the project file from the SSD.

Make sure you have 'Copy all audio with project' checked in the Save As dialog; otherwise the project will continue to refer to audio files from the original location.
 
That said, just copying all project folders to the new drive and launching projects from there should do the trick. I think either you're right that something is up with your Windows config, or you're mistaken that you're launching the projects from the new location. Try moving a test project instead of copying it so there's no chance for any part of it to run from the old location.

I'm not on my daw, is there still an entry for Edit -> Preferences -> File -> Audio Data? Check the Global Audio Folder. There are different ways to store your audio data and it depends on how you do it. What version are you running? Platinum?

Yes, Sonar Platinum 2016.10.  I thought I had it working.  I deleted the original files from the spinning drive, then opened the file from the SSD and they streamed from the SSD.  Then I did a "save-as" with the audio included back to the spinning drive and closed Sonar.  I relaunched Sonar and opened the file from the spinning drive and the files streamed from the spinning drive.  I closed Sonar, relaunched and opened the file from the SSD, and the audio then was streaming from the spinning drive again, not the SSD.

I don't know what else to suggest. I have had my Cakewalk Projects folder on a secondary drive and that works fine, but I've never tried to have multiple folder locations ...

Delete the files from your spinning drive.  Open from the SSD, but don't save as back to the spinning drive, just copy them (and copy them to a new directory not the original one.)

Thanks for all of the suggestions.  Unfortunately, I've tried them all and it still streams from the spinning drive unless I delete the files.  I want to use the spinning drive as an internal backup drive, so I don't want to delete those files.  As far as I know, there is no way to keep Windows from accessing that drive as long as it's connected to the motherboard.  If anyone knows of a way to do that, please let me know. 
 
I still don't understand why it won't use the files on the SSD.  Sonar goes to that drive to open the project file, now that I've changed the folder locations, but even though the audio folder is in the project folder on the SSD, it still goes to the spinning drive for the audio files. 
 
As I stated in my original post, it isn't just Sonar that accesses the spinning drive files instead of the SSD files.  Windows Media Player does also, so I think it must be a Windows issue, but I don't know of any settings to control that.  Can someone enlighten me?