That was Sonar the X3 Producer error message when, during the recording of a vocal, I was stopped dead in my tracks. Very vibe killing. There was a huge transient spike just before it stopped, very audible and obvious in the wavefile.
 
I've got 50GB free on C drive, which has my Cakewalk program files and half a terabyte fee on the external HD I was using for the project file.
 
What gives?!
 
 
 
Win 7 Pro
Intel Core i7-3770 @ 3.40 GHz, 3.40 GHz
16 GB RAM
64 bit op sys
Lynx Aurora 16 ADC w/ AES16e card

Hi. Does this help?
https://www.cakewalk.com/Support/Knowledge-Base/2003187/Audio-Disk-full-unable-to-save-entire-recording
Seems like deleting AUD.INI is the trick.
All the best.

1.Take a look the Available Disk Space readout at the bottom of the Cakewalk window.

 
There isn't any. There is a Performance module in the upper right corner and it says 480GB free on the disc and 17% System Memory Usage.
 

2.If the disk space readout looks like you've got plenty of room, locate the file AUD.INI in the Cakewalk directory, and delete it.

 
I can't seem to locate it.

AUD.INI is located in C:\Users\"YourName"\AppData\Roaming\Cakewalk\SONAR Platinum