Before you post a bug, make sure that:
- the bug has never been posted before. If you are not sure, use the search function;
- in case of crashes, data needs to be unmodified. Better not report crashes that are simply caused by corrupted or broken data, hacked copies, or any kind of tampering;
- in case of crashes, said crashes are reproducible in some way. Also, the best way to figure out rare crashes is by enabling crash dumps. Here's a guide on how to create those.