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Invalid key / Could not activate license

For Pro/Free users




  • Check your internet connection and make sure you can access the web.
  • Open Date and Time by clicking the Start button, click Control Panel, click Clock, Language, and Region, and then click Date and Time


Click the Internet Time tab, and then click Change settings. ...


Click the Update now button

 It is very important to wait for the confirmation message that announces you that the update was successful

If you receive an error confirmation message, please repeat the process until you receive the message that announce you the Update was successful.


Please make sure the license was not used to activate Heimdal Security on another computer. If it was activated on another computer (a new laptop/PC for example) then please contact us at so we will change the key.


For CORP Users

This issue can be caused by 3 things:

1. Time and Data

This behavior can occur if the time or date are not synchronized between your computer and the domain to which you are attempting to log on. You can check and synchronize the computer time with your DC time using command: net time /set /y or w32tm /resync .

You can run this command using the command prompt with administrator privileges.

Heimdal Security Software also depends on Windows Time service. Without it, Heimdal software cannot communicate with the DC time anymore, so it will fail to activate the product license key.

 2. Your Firewall is blocking the connection between the Agent and our servers

Set the appropriate exceptions in your firewall for all of Heimdal's processes and for the local install path.

3. Windows Management Instrumentation(WMI) service

Heimdal application is completely dependent on the Windows Management Instrumentation(WMI) service. WMI detects all active network adapters on the specified computer so it can then add Localhost IP Address, after that, Heimdal will start to filter your internet traffic.

4. .NET Framework

  • The .NET Framework version currently installed on your computer is not compatible with Heimdal V2.

Solution: the current .NET Framework version compatible with Heimdal V2 is 4.6.1 (download link) or above.


  • Or the .NET Framework libraries got corrupted.

When you try to activate your Heimdal V2 license and you get a .NET framework error in event viewer, then the API libraries are most likely corrupted and you need to repair them for Heimdal to work properly.

To open Event viewer, please follow these steps:

  1. Click the Windows Start button > Type event in Search programs and files field.
  2. Select Event Viewer.



Navigate toWindows Logs > Application, and then search in the right panel after Filter Current Log > select Filter tab > Event level > mark Critical, Warning and Error and click OK.



Check in the Application logs if you find errors regarding to Application Error and .NET Runtime and in the logs the Application name is ClientHost.exe.



If this is the case, you can repair the .NET framework installer by using this tool (Download it here). Or you can upgrade to the latest .NET framework version which is compatible with your Windows operating system (please check this documentation). 

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