when c# program crash how to know why?

Exception code 0xc0000374 means you're facing heap corruption.

The most common causes for this kind of error are these two:

• A faulty RAM module
• Buffer overrun, when one thread tries to read something and another thread has removed data in the meanwhile. This shouldn't happen in managed code as far as I can tell.

You probably have to get Windows Debugging Tools to figure out what's wrong if you can't debug the application in the dev environment.