No output file... why?

I'm trying to crack some MD5 hashes but i have a problem with output file, which is not being created. I'm using oclHashcat. When i try SHA1 Hash it works but with MD5 not... why?

cudahashcat64.exe -m 0 -output-file=cracked.txt --remove hash.txt wordlists

i deleted hashcat.pot but the same problem...