Windows Registry Checker creates a backup of varous Windows system files and registry configuration. Windows Registry Checker audits the Windows registry. If undesirable entries are found, then Windows Registry Checker will fix via backup if available or attempt to repair in no backup is available. Windows Registry Checker runs when you start your computer, once a day, and before Windows Setup performs an upgrade. (edit Scanreg.ini to configure) scanreg.exe is the MsDOS/Protected-Mode version of Windows Registry Checker.