Windows permissions can prevent the software from accessing the license file. Right-click the GT Designer3 icon on your desktop. Select Summary Checklist Possible Cause No license entered Use GT Designer3 License Registration . GS21 Series Issue Install GS series support package. Expired Trial Contact local sales office for a permanent key. Version Mismatch Upgrade license to match GT Works3 version. When to Contact Mitsubishi Support
Ensure that all necessary (especially for GS series) are checked. 3. Check for License Version Mismatches
If the software was working previously and suddenly stopped, corrupted cache or configuration folders are the most likely culprits. Navigate to Local AppData : Open Windows Explorer and go to C:\Users\ \AppData\Local C:\Users\ \AppData\Roaming Identify GT Folders
Navigate to the add-on directory, typically (DVD drive)\Disk2\AddonProject\GTSV . gt designer license not found
The software responsible for managing licensing is not running or is corrupted.
Getting the error blocks your Mitsubishi HMI development instantly. This issue happens when the software cannot verify your product ID or license key. It usually stems from registry errors, missing admin rights, or incomplete software installations.
Before diving into the fixes, it helps to understand why GT Designer is losing track of its license: Windows permissions can prevent the software from accessing
Disclaimer: This article is for troubleshooting purposes. Software licensing agreements vary by region. Always verify your license type (Perpetual vs Subscription) with Mitsubishi Electric Automation.
Third-party registry optimization tools frequently delete MELSOFT license keys, mistaking them for unused background data.
If these folders or strings are empty or missing, your installation is corrupt, and the software cannot verify your license. GS21 Series Issue Install GS series support package
The "GT Designer license not found" error is a significant blocker, but as this guide has shown, it is rarely a mystery. By systematically checking the points outlined above—from verifying the installation of the System Driver to addressing software conflicts with antivirus programs and resolving hardware changes—you can diagnose and resolve the issue. For persistent problems, especially those involving version conflicts or add-on licenses, your most effective resource is the official Mitsubishi Electric support network. Your local sales office or distributor has access to the latest technical bulletins, software updates, and troubleshooting procedures required to get your HMI development back on track.
Always use the official Mitsubishi Electric FA site to download updates and environment patches for GT Works3.
This comprehensive guide covers why this error happens and provides step-by-step solutions to fix it. Understanding the Error
(Only for old versions – GT Designer3 usually uses its own system.)