1. Before uninstalling ExtendSim, be sure to revoke the license using the Help > Revoke License Activation command (or the Help > Deactivate ExtendSim command if prior to 10.0.5).
2. After the license has been revoked, use the Windows Settings > Apps and Features to uninstall ExtendSim.
3. Finally, delete the two folders: Documents\ExtendSim and Program Files\ExtendSim. (The remaining contents of these two folders were created after installation. The uninstaller couldn't remove those files because it didn't know about them.)
4. If you're transferring the license to a colleague, see Moving ExtendSim from one computer to another.