why is this happening ?
 

problem is described in the picture above,
i searched all over the forum, i turned on thin cut, adjusted edge criterion, still get this. anyone has an idea ?

Try rechecking association and edge association methods method....

Can you more specific about the geometry

It looks like you have an inside curve which is not relevant. have you done a build topology before meshing ?

thanks for replying,
for the building topology, it is showing me yellow curve. but i don't know which feature to check there when it comes to curves like this.
@nitin the picture below describes my geometry better, look inside the red bubble:
https://dl.dropbox.com/u/35161486/hole_intake_hexa.png