Common (keys read by many parts of IIS) 1. HKLM\SOFTWARE\Microsoft\InetStp\Configuration\MaxWebConfigFileSizeInKB (REG_DWORD) Nativerd.dll uses the value of this registry key to determine the maximum allowed size (in KB) of web.config files. Configuration system will produce error “Cannot read configuration file because it exceeds the maximum file size” if it encounters a web.config larger than this size. Configuration system assumes a default value of 250 (100 in Vista RTM). Changing the value of this key will require a process restart.