Sorry for the inconvenience.
This issue has been fixed with the latest update that is 2015.2.1.
Also check this blog for more information : http://blogs.adobe.com/lightroomjournal/2015/10/lightroom-cc-2015-2-1-6-2-1-now-available. html
Are you sure you are at 2015.2 and not already at 2015.2.1? Crashes upon export are still present in 2015.2.1 from reports here on the forum but 2015.1 shouldn't have had these issues. If your crashes started upon update to 2015.2 and the 2.1 update didn't fix them, your only recourse might be reverting to 2015.1.1 using the instructions here: http://www.lightroomqueen.com/how-do-i-roll-back-to-lightroom-2015-1-1-or-lightroom-6-1-1/
I am having this issue also - Mac Pro 2010 48GB RAM - should not have updated...
I had to uninstall and roll back to 2015.1.1 to gain basic functionality again. It's rather shameful. In the process I lost a couple things. The first is lens profile for the newer Sigma 24-25 f/2 DG ART. The second is tethering capability for my Nikon D810 and D750. The tethering issue is specific to LR on OS X El Capitan however. Of course a couple new features had to be deferred to.
Yes, I have just uninstalled, downloaded, reinstalled and it is working fine. Waste of time however - 11pm and I could have been done 3 hours ago...