How much audio?

It would seem that I should be able to answer this question myself, but I would like some input from the rest of you. 
I was recording audio off of the radio, (captured from my tablet and input through my mixer) and I was just arming a track and letting it play for about an hour or so, and then I would stop the recording, arm another track and continue recording for another hour or so. This went on for about five or six hours. At some point I went into the studio to start another track, and Sonar (Platinum, Newburyport) refused to insert another track. There was no warning, or complaint. No problem with playing back the recorded audio. No problem changing any other settings. It just would not open another track. 
Now before you say it was a memory full situation, I've done this in the past. But I only allowed one instance of a track. I just thought this time it would be easier for me to manage, spread across several tracks. 
I was recording at 44,100/16 stereo. I have a total of two terabytes of hard disk space, both SSD. 
What do you think?