scook
Other way around, a file was imported with Preferences > File > Audio Data "Always Import Broadcast Waves At Their timestamp" enabled. This is the default setting.

That's exactly what I meant to say, however it didn't come out right.
 
Hows this...
""You imported something having Broadcast timestamp enabled""

I think scook's on the right track. SONAR was forced to switch to a 64-bit file because your project exceeded the usual 2 GB limit. Open your project and press CTL-End to move the cursor to the end of data. You'll probably find it's WAY past where you think the project should end.

bitflipper
I think scook's on the right track. SONAR was forced to switch to a 64-bit file because your project exceeded the usual 2 GB limit. Open your project and press CTL-End to move the cursor to the end of data. You'll probably find it's WAY past where you think the project should end.

Exactly, although I think the .wav limit is 4GB, but either way really large files need to be w64.

It is 2GB. The conditions which trigger Wave-64 file creation are documented here  http://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Recording.07.html
 

Again, thanks for all the input and in such a timely manner.

scook
There may be data beyond the "end of the song." Automation nodes and MIDI data are the usual suspects. Either use a time range selection for export or clean up the data past the end of the song.

Cheers Scook... I was pulling my hair out over this one.....On a 45 minute file as well so you can imagine the file size...
Nice one! :)