Vray has been know to cause problems for some people's setup, so I mentioned it specifically. But other extension can also cause issues.
To test, disable all extensions. Disable from inside SU is one way, another is to temporarily rename the Plugins directory so none of those extension load at all. If no crashing, restore half of the extensions in the Plugins directory, and test for crashing by running SU as usual. If all's well, add back 1/2 more extension. This is binary tree testing methodology.
With extensions, if you can ID the one(s) causing crashing, then it's time to report the issue with the extension developer - the one who is responsible for maintaining the extension's compatibility with SU.