Also there is so many different computer software and programs out there, and new software always coming out...So I would say "New Compatibillity Issues" Sometimes people install rogue software and programs...That is why I think this Sandbox in the Free version was an awesome idea....It will definately keep the Avast team busy, but in he long run it will help them determine and analyze new malware and build their Malware samples database much faster than the competition, and make your computer safer....