We would need to investigate the 3dm file that crashes when opened to determine whether its V-Ray data is retrievable. Could you please send it over together with its associated asset files at email@example.com via a file-sharing service of your choice? Make sure to add a link to this forum thread and state the version numbers of V-Ray you have used for this project as well as the one you currently use.
On a side note, every time you experience a crash while using V-Ray for Rhino, please fill in the Rhino crash report form, add a detailed comment and submit it. McNeel shares all error reports caused by V-Ray with my colleagues here at Chaos Group. This data helps our developers to pinpoint the causes of each reported error and implement solutions in a timely manner.
V-Ray for Rhino QA