When I export audio with file -> export -> audio, it creates a wav file like its supposed to. However, only the first few seconds of the file play properly, after which, the duration is replaced with complete silence. The same problem occurs when I bounce to clip, or bounce to track.
At earlier stages in the project, these functions were working perfectly. Now, for some reason, they do not.
Has this happened to anyone else? Any suggestions?

In case any of this is relevant:

Audio driver bit depth is 16,
sampling rate is 44100
Buffers in playback que is 4.
I've tried running WAV profiler, but it doesn't seem to have an effect.

I use Sonar X1 producer
I use a Behringer UControl UCA222, and I've also tried these operations without the Audio Interface connected. Makes no difference.

Thanks for any help.

Make sure you dont have just a portion of something selected somewhere.

What Id try is click off in the Track View in a blank area then hit the rewind to beginning

You can also hit Cntrl A to select all and then export - Im usually not into selecting but have done it in the past. 

yeah, it sounds like you are inadvertently selecting the first clip in a track/project rather than the entire project. 

Be sure to slide the track view out to view the entire project time line. Be sure ALL the tracks and all the clips in those tracks are selected. 

If you simply double click on the track inspector a few times it will cycle through clips, track and project. 

Another way is to hold CONTROL while clicking exactly what you wish to select. 

I like the "click through until I get the whole project selected", then I simply mute (before or after selection) the tracks I do not want in the export. 

Hmmm...How does the export actually work: If you accidentally select only a few second clip in the beginning of the project, does the export also contain the rest of the project length silence? I think not?? It should then export only the selected clip, shouldn't it? Note, that the OP says it's the same thing when bouncing to clips, where I assume he is selecting the clips to be bounced, and still gets only a few seconds of bounced material - if I undestand/read correctly.
Or could this be an export source-selection issue??

It was just my 2 cents worth Kalle but I have managed to do it in the past when slip editing or something and have just a portion selected not thinking when exporting and same thing.

Even bouncing will yield the same effect on my system. IIRC you can have a portion selected and still select the track to bounce without effecting the portion selected in the clip and come up short like this.

We will have to wait and see if he finds what caused it though.