meshing

Hello, 

I have a question about the software hypemesh, sometimes i mesh with the same parameters but i find a different meshing  I wiill explain more for you ,

once I lmeshed with  a specific  parameters after I found A lot of error ,the software could not launch the calculation. Another time I lmeshed with the same parameters but I found different results and the software launched the calculation even if there were quite a few errors. Idont understand anymore how hyperresh works if you have explanation for it i will be grateful .

Thank you