Purpose

The purpose of this document is to highlight a Microsoft Windows Task Scheduler bug that can cause your scheduled console tasks to run a week early or not at all.

Symptoms

The Ivanti Patch for Windows Servers console is installed on Windows Server 2016 or Windows 10, and you have a monthly console task that is set to run on a specific occurrence of a day of the week (4th Wednesday, 2nd Saturday, etc.).  Occasionally, this task executes exactly one week early or not at all.

Cause

Microsoft has confirmed a bug in the Windows Server 2016/Windows 10 Task Scheduler that will execute scheduled tasks one week early or not at all when specific conditions are met:

• The month does not start on Sunday
• The monthly task is set to execute on a specific occurrence of a day of the week (4th Wednesday, 2nd Saturday, etc.)
• The date the task is scheduled to execute is a multiple of 7 (7th, 14th, 21st, or 28th)

If these conditions exist and the task is scheduled to execute on the 7th, the task will not run.

If these conditions exist and the task is scheduled to execute on the 14th, 21st, or 28th, the task will execute one week early.

This calendar from Microsoft's TechNet post regarding the issue illustrates the affected days of 2018.  Tasks scheduled days circled in red will execute one week early, while tasks scheduled on the days circled in grey will not execute.

Resolution

There is no workaround, but Microsoft is aware of the issue and is working on a resolution.

Additional Information

Microsoft has acknowledged this issue and describes it further on their TechNet AskCore Japan blog:

https://blogs.technet.microsoft.com/askcorejp/2017/12/11/mouthly_tasks_issue/

Affected Product(s)

Shavlik Protect 9.2.x

Ivanti Patch for Windows Servers 9.3.x