On some installers I get this message about testing installer integrity (or something to that extent) and I was wondering... What is that all about? does Windows look at the installer for viruses or something. Is this something the installer is supposed to do? Why does it only show up on some installers?
All the installers and launchers have a built in self-CRC check to ensure they've been unchanged. They can detect if the download was incomplete, if the download was partially corrupt or if it is infected by a virus, in which case the CRC check will fail and it will abort.
Sometimes, the impossible can become possible, if you're awesome!