Many malware disable network and target software such as Mbam to prevent downloading or internet based installation. Chameleon doesn't help in those situations. I am currently battling a PUP/malware that creates incredibly slow download speeds. Malwarebytes runs, but won't update (times out). I've verified this with chameleon as well. So it is imperative that we always have a way to update virus defs offline. Copying a rules.def file is perfect. Thanks for this. But... I had to dig through the forum to find it this method for 2.x. I knew the old 1.x way and have used it many times. Is there a reason this is not readily available on the downloads page? Malwarebytes Rocks!