Shontoon we are going to need way more information then what is provided to help you.
tell us the comp. type your on and its specs, how big is the file your exporting, what steps do you take leading up to the crash, are you generating a crash report and if so can you post?
It happened again here is the problem report also I running on Mac OS X Yosemite Version 10.10.1 Mac Mini Processor 2.5 GHz intel i5 Memory 4GB Intel HD Graphics 4000 1024MB
If you have dropbox installed on your computer, can you uninstall it and let us know if you still have issues?