How much free space do you have on your system drive? This can sometimes cause an issue when burning if you have limited space.
The other option that normally resolves the issue is deleting the find preferences fie.
Have a look at this article which walks you through the process:
Some Mac users may occasionally run into issues with Finder, discovering that Finder will misbehave wildly, sometimes becoming very slow and unresponsive, crashing, or using inordinately high CPU. …
osxdaily.com