UAC Heuristics

If you run an application setup file, UAC will prompt you for administrator credentials. This makes sense because most installation routines require elevated privileges. However, installers created before Windows Vista do not include a manifest, so Windows Vista and Windows 7 have to detect heuristically which executables are setup files. By contrast, 64-bit executables always have a requested execution manifest.

To do this, Windows examines 32-bit executables without a requested execution level manifest that would be run with standard privileges. If the executable meets those requirements and has a filename or metadata that includes keywords such as install, setup, or update (or several other indicators that it might be an installer), UAC prompts for elevated privileges before running the file. If UAC does not prompt you for administrator credentials for an install, right-click the setup file and then click Run As Administrator. Without administrative privileges, most installations will fail.