An operation fails in Plesk for Windows Server: Cannot connect to the task manager (plesk-task-manager service might not be running)

Symptoms

• An operation fails in Plesk with the error message:

  PLESK_ERROR: Cannot connect to the task manager (plesk-task-manager service might not be running): Unable to open named pipe stream: The system cannot find the file specified. (Error code 2) at Unable to connect to pipe ...

• The Plesk Task Manager service does not exist on the server:

  C:\> sc query "PleskTaskManager"
  
  [SC] OpenService FAILED 1060:
  The specified service does not exist as an installed service.

• In an attempt to install Plesk Task Manager with the command:

  C:\> "%plesk_dir%admin\bin\defpackagemng.exe" --update --type=psa.task-manager --package=task-manager --fix

  nothing changes or the operation fails with the error message:

  PLESK_INFO: Use of application NS Service Manager has been blocked by your Administrator

Cause

Plesk Task Manager requires nssm service which fails to be installed or its installation is broken. This may happen when antivirus/firewall blocks it.

Resolution

Note: Before proceeding, exclude the Plesk folder %plesk_dir% (by default, C:\Program Files (x86)\Plesk\) and C:\ProgramData\Plesk\Installer from antivirus/firewall scans or disable antivirus/firewall temporary.

1. Connect to your Plesk server via RDP.

2. Go to C:\ProgramData\Plesk\Installer\cache\pool\release and search for "plesk-nssm.zip.tmp". If the .tmp file is found, delete it.

3. Open https://autoinstall-win.plesk.com > PANEL-WIN_18.0.XX > dist-windows and download plesk-nssm.zip.

4. Unzip the package.

5. Copy all unzipped files to C:\Program Files (x86)\Plesk\nssm.

6. Copy nssm.exe to C:\Program Files (x86)\Plesk\PleskTaskManager (if it does not exist).

7. Install Plesk Task Manager Service:

   C:\> plesk sbin defpackagemng --update --type=psa.task-manager --package=task-manager --fix

8. Verify that the PleskTaskManager is installed:

   C:\> sc query "PleskTaskManager"
   
   SERVICE_NAME: PleskTaskManager
   ...
           STATE : 4 RUNNING