Windows – stopping a service created via NSSM does not work

If Syncthing is installed on Windows as a service using NSSM, exactly as described in the documentation (--no-restart --no-browser --home=""), including the subsequent “final settings” (step 12), then after the initial service start (sc start "service name") it cannot be stopped by any means. The stopping process eventually times out, but the service never terminates. It cannot be stopped from the command line via SC or NSSM, nor from the GUI / MMC. To stop the service, it is necessary to kill the NSSM process.

This behavior was reproduced on two different Windows installations (Windows 10 LTSC and Windows Server 2019), with identical installation procedures, exactly according to the guide. The NSSM version was the latest available. The behavior was identical.

Workaround: After starting the service, stop Syncthing at least once from the browser/web interface running at ip:8384 (Actions / Restart). After doing this, the service can be stopped and started normally via MMC or from the command line (SC / NSSM). Until this is done, the service cannot be stopped.

Start with the Windows service setup and final settings described in the documentation, using the reported NSSM procedure. Reproduce the failed stop on Windows, then compare it with the browser restart workaround. Done means the service-stop behavior is explained or corrected in the documentation, with the workaround and expected result verified.