This error directs you to search for cracked files from torrent and other alternatives. This pop-up is very annoying because it appears every time you will download several files or when you start your system. But you might face pop up that ‘ IDM has registered with a Fake serial number‘. I would say, this is from one of the best tools to use to download files from the internet. You might have used this application because it helps you download files from the web at high speed. Fix IDM Fake Serial Number Error – Almost everyone knows about the ‘ Internet Download Manager‘ (IDM).