After reading some reviews on various websites, it appears that PC Clean Maestro is actually one of those apps that force you to buy them in order to fix your computer. I recommend its immediate removal because it can do more harm than good to your PC.
Instead of using PC Clean Maestro, visit the application's page at Software Informer and get CCleaner. It's miles ahead of PC Clean Maestro and keeps your computer safe as well without interfering with other applications installed on your PC.