lm hash

[mastercracker]

i get a 20 hash off lm.

i try to crack them with a hashcat all the char A-Z,a-z0-9 and ?s but the hashcat success to crack only 6 password?

how it can be? this is a lm!!

First, you don't need a-z, just A-Z but it's possible that hashcat ignore it anyway (just don't assume it). Second, I doubt that you went up to 7 characters long on CPU. Third, post your command line so that we can make sure everything is o.k.