Select . Some versions allow you to "Repair" or "Re-enter Product ID" without a full reinstall. Check for Conflict with "MELSOFT Selection" :

: If your font size is set to "Large" or custom scaling in Windows, some GT Designer dialog boxes

Troubleshooting "GT Designer License Not Found" in Mitsubishi GT Works3

Furthermore, the error serves as a case study in the challenges of lifecycle management in industrial IT. Automation software often has a lifespan that far exceeds that of typical office software. A factory may run the same version of GT Designer for a decade to maintain compatibility with legacy machinery. However, modern operating systems evolve rapidly. When an engineering workstation is upgraded to a newer version of Windows, the legacy licensing services associated with older versions of GT Designer may become obsolete or incompatible. This creates a "zombie" software state where the application is installed, but the licensing verification architecture is broken. Consequently, the "License Not Found" message is often the symptom of a broader IT/OT (Information Technology/Operational Technology) convergence gap, where the rapid pace of IT updates clashes with the static stability requirements of OT.

In some versions, specific Windows settings can interfere with how dialog boxes and license prompts appear. Font Scaling

The software was installed without entering the license key, or the installation process was interrupted.

Re-enter your valid (Serial Number) and name, then click Register or Next to overwrite the corrupted license file. Step 3: Repair or Reinstall Using the Original Media

may fail to display correctly, leading to hidden errors. Set Windows scaling to 100% (Normal) Regional Settings : For older versions (GT Designer 5/6), ensure your Windows Regional Settings are set to

This error usually happens when the application's configuration files become corrupted or when there is a mismatch with the main vMix license. Corrupted Config Files

Whether you've just reinstalled the software or it suddenly stopped working, Common Causes of the License Error

: High-security settings may block the licensing service. Temporarily disable these to see if the software launches, then add an exclusion for the application. System Permissions : Try running the application as an Administrator

The software was installed on an Administrator account, but a standard local user account is attempting to run it without shared permissions. Step-by-Step Troubleshooting and Fixes

If the error occurs when opening a project, the internal library configuration might be corrupt. Navigate to %APPDATA%\Local\MITSUBISHI . Locate and backup the folder named GTD3_2000 .

is required. This involves uninstalling the software, manually clearing the "MELSOFT" folders in the Program Files and AppData directories, and then reinstalling using the original Product ID. It is also crucial to ensure that the version of GT Designer being used supports the specific HMI model being programmed, as older versions of the software may not recognize licenses intended for newer hardware iterations. The Impact on Productivity