Not able to block download using regular expression in squidgurard?

[coffemug]

Hello

I am using pfsense 2.4 with squid and squidguard, i cant block extensions like .exe on my browser .

i use this code
(./..(exe)) and its no use. then i tried
(./..(asf|wm|wma|wmv|zip|rar|cab|mp3|avi|mpg|swf|exe|mpeg|mp.|mpv|mp3|wm.|vpu)) and paste under Target categories and regular expression but its still allowing downloads

How to block downloads using pfsense and squid .

thanks