- Plesk 12.0 for Windows
When trying to run a disabled scheduled task manually, Plesk shows that the task was launched successfully.
However the task was not launched and the notification email with confirmation was not sent.
Such behavior is known bug #PPPM-3913. It was fixed in Plesk 12.5.
Upgrade to Plesk 12.5 or higher.
As workaround for Plesk 12.0: