Well there reason Purge' asked is becuase you haven't given us enough information, It could be a million different things; from a once in a lifetime crash that happened multiple times in a row (Im geussing not), to a virus on your computer.
If you can't be more specific then your going to need to upload screenshots or even a video of what happens or upload your map so somebody can check it for you.
🔨 Hive's 3D Viewer has been updated! 🔨 It now supports MDX1100 which should fix a lot of issues when viewing HD models in our 3D Viewer. We encourage you to check it out for yourself and report any issues you find in the Site Discussion board.