client crash loading normal game champion select

my client crash often since 7.2 or earlier. After i press accept (AT NORMAL-BLIND) , it very often crash when tries to load the champion select,no errors have been shown so far, just instant program-closed without any ''stopped working'' errors. how can i this?

do i need add logs? where to find ? btw i use legacy client

e: sorry i should post this at help subforum, mb, i guess