Windows Service Error 1056, "An instance of the service is already running"

Error 1056 means the service is already running, so there is nothing to start. It usually appears when a script, an installer, or a second copy of a program tries to start a service that is already up.

The fix, in order

  1. Check the service status first. In Services, look at the Status column. If it says Running, the service is already up and the error can be ignored.
  2. Confirm it from the command line with sc query followed by the service name. A STATE of RUNNING means the same thing.
  3. If the service should not be running, stop it with sc stop and the service name, or the Stop button in Services, then start it again.
  4. If the service looks stopped but still reports 1056, restart the PC. A service process can be stuck in a stopping state that only a reboot clears.
  5. Check for a duplicate installation. Two copies of the same program can register the same service, and the second one always fails with this error. Remove the duplicate.
  6. If an installer keeps failing with 1056, stop the service before running the installer, since many installers try to start a service that is already running.

If it still happens

If the service reports 1056 but is not listed as Running anywhere, check Event Viewer for a service control error, and check whether a second PC management tool is starting the same service at the same time.

Common questions

Is error 1056 a real problem? Usually not. It is Windows saying the service is already running, which is the state you wanted. It only matters when an installer or script treats it as a failure and stops.

How do I stop a service that is stuck? Use sc stop and the service name in an admin Command Prompt. If it stays in a stopping state, restart the PC, since a stuck service process cannot be forced safely while Windows is running.

Related errors

Windows Service Error 1062 · Windows Service Error 1060 · System Service Exception

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