Any idea how to determine what the actual filename is when the dialog box is too narrow to actually see the path to the file?
 

here is screenshot
http://i1022.photobucket.com/albums/af344/timeking/Sonarfilenamenotreadable_zpse7feb643.jpg
 

This is not a serious problem (yet), but without the ability to CleanDisk, all those bad takes are going to pile up and eventually fill my harddrive.  Am I not being clear as to what my question is?  Is the only 'fix' to open all my project files one by one and see which one is corrupt?  that would take days.... 

I wish I had an answer for you. I have not used anything other than the "Save As" function to clean projects since the introduction of per-project audio folders.

Yes, you ~could~ clean a project by SaveAs to a new ProjectFolder, and then delete the old folder.  That would work IF you knew which Project was had the corrupt wrk file, which in my case I don't.  I only know that some wrk file somewhere has taken a crap, but not which one.  I guess the only way to resolve this is the brute force method of going through every one of my wrk's (or whatever the extension is).  As Sonar is currently coded, the CleanAudioDisk is only useful as long as you don't have a corrupt file, in which case you don't know what it is unless you are keeping all your projects near the C:\ root of your harddrive.  Bummer.

The text of many dialogs may be captured in the Windows clipboard by pressing CTL-C. I have no idea if that'll work for this particular dialog, but the trick works with all Windows messageboxes and with programs that utilize Windows messageboxes for their own dialogs. Once in the clipboard, open Notepad and press CTL-V.

My guess is the unreadable file is not even a SONAR file, but a file from some other app that uses the same extension (.TPL for Template is quite common). If Dave's tip doesn't get you the full path, you can search whatever part of the path is visible for that extension, and I wager you will find a non-Cakewalk file.

If you can't copy/paste the string, try this program:
 
http://www.nirsoft.net/utils/sysexp.html
 
It allows you to save text from internal Windows parts - very useful.

Well I "knew" that the Crl-C Ctrl-V wouldn't work, but I tried it anyway, and sure enough, no worky.  HOWEVER, the sysexp.exe program did capture the contents of that window, and it turned out to be a truncated .cwp file of a previous version of one of my projects (I name projects Song v01, song v02, etc., periodically saving to same project folder ... that way I can always go back a level and retrieve something I screwed up [a procedure I learned the hard way in Microsoft Word]).  SO MUCH THANKS!!
 
PS:  You can tell I"ve been a long-time Cakewalk user since I referred to my .cwp files as .wrk.  Silly me.