You may receive the following error message from GuardedID after updating your PC to Windows 10 Version 1809 (released October 2nd, 2018):

"[NotifyDriver] Failed to deliver keydown event to the driver -> ERROR 6: The handle is invalid."

If you are receiving this error message, right-click the GuardedID taskbar notification area icon then select "Check for Updates" to download and install the latest version of GuardedID which resolves the issue.