Hi Christian,
You need to follow the deactivation procedure on the computer where the license was activated. Perhaps, you are using a Floating User license, and it means that your license was activated on some server in your network. If you deactivated the license on the computer where TestComplete is installed, but the license was activated on another computer, you would get this exact error. Please check this.
If this doesn’t help, please do the following:
- Go through the Licensing Troubleshooter as Ravik suggested: https://support.smartbear.com/troubleshooter/?prod=Licensing
- Contact our Licensing Experts here: https://support.smartbear.com/product-list/