Restart your PC. When G Data starts, it will believe it is a fresh install. You should see a "30-day trial remaining" message.
If you already have a license and need to continue service, you can extend your license directly through their portal to keep your virus signatures updated every hour. Try G DATA Antivirus programs for free g data antivirus 2013 trial reset
: Modern security software (and even versions after 2013) shifted to cloud verification. Instead of checking a file on your hard drive, the software checks a unique hardware ID against a server. If that ID has already used a trial, deleting files on your PC won't help. Security Risks Restart your PC