G DATA Support - FAQ
Support Code: 22009

The service “G Data Security Client” is not able to start with the error message "Error 1: Invalid function"

This article will show you how to solve a particular technical issue resulting in the service “G DATA Security Client” not being able to start on a Business client computer with the following error message: "Error 1: Invalid function".

This information concerns older versions of G DATA products. We are currently reworking the article and will it be updated in the near future.

This is a rare issue which could happen after a software update to, resulting in the G DATA Driver Framework not being correctly installed.

As a result, the G DATA Security Client service can’t be started.

To solve the issue proceed as follows:


Step 1. Start a Command Prompt as Administrator.

Step 2. Use the command “cd” to navigate to the installation folder of the Security Client, which is by default:

"C:\Program Files\G DATA\AVKClient" on a 32 bit OS.

"C:\Program Files (x86)\G DATA\AVKClient" on a 64 bit OS.

Step 3. Enter one of the following commands:

“ avkwctl.exe /OnUpdate” on a 32 bit OS.

“ avkwctlx64.exe /OnUpdate” on a 64 bit OS.

If everything worked you get no further notification, if there was an issue you will see an error message.

Step 4. Reboot the computer.


Step 5. The issue should now be solved.

Last change:

Operating system:

 Managed Endpoint Security
 Endpoint Protection Business
 AntiVirus Business
 Client Security Business