Parallels

Symptoms

When trying to add or remove scheduled tasks in the Plesk scheduler, The following error message is displayed:

SchedulerManager::set() failed: listmng failed: Unable to restore user scheduler:
System.ArgumentException: The parameter is incorrect

Cause

Windows task scheduler is not functioning properly. It cannot create/delete tasks. Most probably, the reason of this issue are corrupted RSA keys in system. RSA keys are stored in the  %ALLUSERSPROFILE%\Application Data\Microsoft\Crypto\RSA folder.

Resolution

Corrupted RSA keys need to be removed using the following steps:

1. Stop the Windows Task Scheduler:

Start, Run, type sc stop Schedule

2. Rename the S-1-5-18 and MachineKeys folders in

%ALLUSERSPROFILE%\Application Data\Microsoft\Crypto\RSA

3. Restart the Windows Task Scheduler

Start, Run, type sc start Schedule