And the first "TIP" window that comes up in X3 tells you to save CWB
But Let it be known, CWB is not reliable like it once was.

Did you know that SONAR allows you to choose several file
types when saving projects?
CWP Files - A CWP file contains MIDI dad, project-specific
settings, and reference to all audio data that resides in another
location - the current Data Directory which is set in SONAR'
Options, Audio, Advanced Tab

CWB Files - Bundle files contain all the data in a .CWP file in
addition to storing the actual audio data used in this project
 
 
There should be a WARNING that the CWB Files have been known to have problems since SONAR 4
and you should always backup with other methods as well. Such as copying your Per Project Folder.
And save as .OMF

Cakewalk's NATIVE file system saving file "CWB"  has serious issues now, loss in your audio data.
I am one of the unfortunate registered users that has experienced this with a paid client with a deadline
and band members from 2 different countries! And SONAR tech support did not bother to respond still after 2 weeks.

So now the big question remaining is still why do they work for some poeple and not others. Has no one any insight into this? I see the mention of Audio snap. IS there then the possibility that only projects that may contain certain elements, like audio snap as example, are the ones that go south? 
 
It seems odd to me that so far there's no real solid understanding here about what it is that does go wrong. And why.  And the reason I ask is not for me, as I said I have avoided them because of the many negative posts,  I became curious with Dofka's legit complaint on the old Sonar forum which it seems Cakewalk themselves will not even answer. 
 
Someone said that Cakewalk has the means to recover his files for him, this would be a good thing if it is true. 

I don't think you can bundle up a file that contains any active Audio Snap processing. From memory you get an explanatory message when trying to create a bundle.

Further to above post to confirm:

From reference guide page 835

"Bouncing AudioSnap and stretched clips SONAR includes a command to select all AudioSnap and stretched clips.
The primary use of this command is to quickly select all stretched audio clips before you use the Track view Clips> Bounce to Clip(s) command.
There are two common reasons why you may want to bounce AudioSnap and stretched clips:
•To free up CPU resources during playback.
•In order to save a bundle (.cwb) file, which does not support AudioSnap data."

just yesterday i tried opening up a couple .cwb files from 2007 & both would not open due to being corrupted.  this has happened to me numerous times. the "remedy" (opening in safe mode) is a joke because nothing opens, just a blank project.  cakewalk should do something about this: either write a utility program that fixes this, or start a service where someone will uncorrupt the .cwb

vintagevibe
Never had problem and have used them for 20 years.

You have had a charmed life. :-) I stopped using them ages ago after getting burned. It was repeatable, they would supposedly be generated without errors, but they were corrupted during creation. Could have been my old daw and not cakewalk, but either way I decided it was a bad idea to have all of my eggs in one basket.

wetdentist
just yesterday i tried opening up a couple .cwb files from 2007 & both would not open due to being corrupted.  this has happened to me numerous times. the "remedy" (opening in safe mode) is a joke because nothing opens, just a blank project.  cakewalk should do something about this: either write a utility program that fixes this, or start a service where someone will uncorrupt the .cwb

Did you open them in the same Sonar that created them or in a newer version? Was it created in 32 bit and opened in 64 bit? Just curious.

[Deleted, had a good thread to point to but was too messy]
 

@wetdentist: Did these files open before? Did you check them after you created them?

And I have been hearing about corrupted bun files before Sonar4. It didn't start then.

Grem
And I have been hearing about corrupted bun files before Sonar4. It didn't start then.

Correct, I stopped using them before SONAR came into existence, back in the Pro Audio days.