Keil Logo

GENERAL: Dongle: Missing Device - Driver Not Installed

Information in this article applies to:

  • C166 Version 4 or higher
  • C251 Version 3 or higher
  • C51 Version 6 or higher
  • MDK Version 4 or higher


During compilation, I receive the following warning message:

Warning 500:

What does this message mean?


This message indicates that the compiler cannot detect your security key. If the Sentinel SuperPro does not work, there may be a problem with the driver.


  • Re-download the current Sentinel Protection Installer.
  • Unplug the Sentinel dongle device.
  • Install / reinstall the driver. Important: When running the Sentinel Protection Installer, in the InstallShield wizard, for the Sentinel System Drivers, the Parallel Driver must be installed (even for a USB dongle, even if there is not a parallel port on the PC). If this is not done, the Keil µVision tools may not recognize the dongle. See the screenshot below:

  • After installation, reboot your computer.
  • Connect Sentinel dongle device to the PC - Windows should recognize it.

    If the WARNING 500 includes a message other than DRIVER NOT INSTALLED, make sure that you have connected the security device correctly to the port of your computer.

    If you still receive this error after checking your security key and its connection, see the suggestions in GENERAL: Installation problems with USB security keys (dongle).




The following Discussion Forum threads may provide information related to this topic.

Last Reviewed: Monday, December 16, 2019

Did this article provide the answer you needed?
Not Sure
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.