Sonar Errors and Workarounds
From Sonar
Information about errors, crashes and other problems with Cakewalk's Sonar DAW software, and ways to deal with them.
Error Messages
Unable to save entire recording. The audio disk may be full.
This error seems to have little or nothing to do with the amount of free space on the audio drive. In fact, users with up to 30 GB of free space have run into it. It is apparently a sort of general error message that Sonar gives under a series of as-yet undetermined circumstances.
Possible work-arounds mentioned by users include defragmenting the offending disk and resaving the entire project in a different folder, making sure to copy the project's audio data to the new folder.