How do i remove this Guest User / greyed out remove button One day i got some malware on my mac. Finally removed it successfully, but this was somehow created when i first got the malware. All the forums i've found just say hit the "-" aka remove but it is grey'd out and i cannot do that.
You can not delete the Guest User.

What you are seeing is the correct behaviour for OS X; the minus button (-) is automatically disabled when the Guest User account is selected.

You appear to have disabled the Guest User account by unchecking all the options. This is enough to stop anyone logging in as guest on your Mac.