Corrupt Projects

Audacity has corrupted two projects that I spent considerable time on. Is this a common feature of this program? What can I do to prevent this kind of corruption in the future?

Thanks,
Ned

No, not unless you have extremely long recordings (greater than 13 hours at 44100 sample rate).
What are you doing and why do you think Audacity is corrupting the projects?
Which version of Audacity on which version of Windows?