I am trying to pay an older previously recorded song in Sonar X1 and getting the error "unable to open audio record device.  device may not support the current projects audio format."  Based on reading some forum posts I think its because the songs sample rate does not match the sample rate I have set in Sonar.  I can't seem to find the sample rate of this song... can someone direct me as to how to find it and then how to change it or convert it to a rate that will match.

That message usually comes when your sound card and SONAR are set to different sample rartes.
Not the file.

What interface are you using?
 
It's probably a good idea to list your specs in your sig, so people can assist better.  This can prevent ending up as a pool of bubbles and tears..

That will happen if another program has your sound card locked and set at a different sample rate to a project. WMP or flashplayer open anywhere?

If that isn't the problem AFAIK project sample rates can only be changed by bouncing each track down at a different rate and then recreating the project. Of course that's not an easy option though.

The sample rate and bit depth of the current project is on the control bar, directly underneath the Now Time, to the left of the tempo/meter and to the right of the Run/Stop/Reset Audio Engine buttons. The background is light blue. I know... took me awhile too. Quite an awkward place. Pretty sure there is no canned option to convert a project's sample rate, but somebody else chime in otherwise.

preferences .. file .. change render bit depth. if you want tochange bit depths of prerecorded tracks use bounce to tracks.

checked in preferences and the record bit depth (16) and render bit depth (32) match my other recorded songs that work fine.  IF I go the bounce to tracks route will i still be able to edit the tracks afterward?  The song in question is still unfinished. 

Yes you can edit afterwards but.....and it's a big but... you have to effectively start the project from scratch as a new project. If you simply bounce them down at a different sample rate and re-import them into the existing project Sonar will simply reconvert them as they are imported which rather defeats the object.

You need to change your "sample rate for new project settings" which are in Prefs-->Audio--->Driver settings, start a new project and import all the converted waves into that.

It's not quick but I have done it several times.

Look on the bright side at least all tracks can be exported in one go using "tracks" as the source category in the export dialogue.

This is all helpful, but for me I had a project which seems to have magically opened as 48k/32 and will no longer play. I have only ever used the default sample rate for projects, which I believe is 44.1k. One day the project works, the next, it doesn't.
 
I tried to set my Focusrite 6i6 to 48k but it says another app is streaming audio, even when no apps are open. I also tried switching off that stupid Cortana and restarting, but nothing helps.
 
I have two sessions to do this week and Windows seems to have a mind of its own.
 
The world's gone mad.

The sample rate of a SONAR project is set one of two ways and magic is not one of them. If there is no audio in the project uses the "Default Settings For New Project" Sample Rate in Preferences > Audio > Driver Settings.NOTE: this setting is used for ALL projects new and old that have no audio clips. If a project has audio clips, SONAR picks up the sample rate from an audio clip in the project.
 
If the Focusrite is the default audio device, it may be necessary to change the sample in Windows before running SONAR.