If you got that error “unable to validate the installation” or “Setup is unable to validate installation” when reinstalling Daemon Tools, and you’re unable to either uninstall/reinstall/run Daemon Tools, do the following:
1) Remove completely the Daemon Tools folder manually, it’s usually C:\Program Files\Daemon Tools
2) Then reinstall Daemon Tools with the installer.
There’s no 3) unless you want to remove Daemon Tools at this point 🙂