Modern versions of GT Works3 allow license binding to the PC's hard drive (Software License) instead of a USB dongle. The error appears if the software is looking for one type but finds the other.
The Fix: Run the License Transfer Tool
Before fixing the error, you must understand what GT Designer3 is looking for. Mitsubishi Electric uses a tiered licensing model. The error message changes slightly depending on the version, but "License Not Found" typically refers to GT Designer3 (Version 1 or Version 2).
If you have tried all the above and still see "License Not Found," you may have a hardware failure or a corrupted activation server record. Gather the following before calling your distributor or Mitsubishi support: gt designer license not found
Pro tip: Mitsubishi licenses have a "recovery" feature. If you’ve lost your license due to a hard drive crash, you can request a License Recovery Certificate from your regional Mitsubishi office. They will issue a new key if you prove the old PC is decommissioned.
GT Designer relies on a Windows service called "Sentinel LDK License Manager" or "HASP License Manager."
How to restart it:
GT Designer3 relies on a background service called the MELSOFT Activation Utility or License Manager. If this service is disabled, stopped, or crashed, the software cannot ping the license server even if the license exists.
If the service is running, the license file may have lost its registry link.
Look for:
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\MELSOFT\LicenseManager
Or:
HKEY_LOCAL_MACHINE\SOFTWARE\Mitsubishi\GT Designer3\License
If missing keys – repair installation.