Several actions in Plesk are queued/stuck: Cannot read process exit code from file

Symptoms

• Several actions on Plesk cannot be completed, e.g. adding a new domain, extension, or updating a site plugin via WordPress Toolkit:
  

• The following could be found in %plesk_dir%adminlogstask-manager.log:

  ERROR 2021/09/27 08:06:20 task=223 process=223 Cannot read process exit code from file 'C:ParallelsPleskvartask-manager/runtime/223/223/status.txt'
  ERROR 2021/09/27 08:06:20 task=223 process=223 Cannot parse process exit code: strconv.ParseInt: parsing "": invalid syntax

• PleskTaskManager is running in Plesk Services Monitor.

Cause

The Windows OS was upgraded in-place, or there are 3rd party services installed on the server that conflict with PleskTaskManager.

Resolution

Migrate Plesk to clean installation of Windows OS.

As a temporary workaround the steps below can be used:

1. Connect to the server via RDP.

2. Open Start > services.msc.

3. Find the "Plesk Task Manager Service" in the list and restart it.