You can delete timer job only with PowerShell. Why? I guess you know why 🙂 The most popular reason is the duplicating of timer jobs. To delete a timer job, you need to know the ID. And you can get it also with PowerShell or with GUI.

How to get SharePoint Timer Job ID form PowerShell

You can get SharePoint Timer Job ID form PowerShell with this command:

Get-SPTimerJob | Where {$_.Name -like '*timer job name*'} |select Id, Name, LastRunTime

The result is here:

Obviously, you can easily copy the Id.

How to get SharePoint Timer Job ID with GUI

You can get SharePoint Timer Job ID with GUI, you should open a timer job definition in a browser (Central administration) and you can find it in the address bar

To delete a SharePoint timer job, you need to get the object and then to call the method Delete

$Timerjob = Get-SPTimerJob -id '35583df1-6d82-4eb5-a059-ed93fd7b9ede'

$Timerjob.Delete()