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Fix Microsoft Project Custom Calendar Not Applying to a Task

Algirdas Jasaitis Oct 20, 2026 868 views

Question details

A custom calendar created in Microsoft Project fails to apply to a specific task even after being selected in the Task Information dialog.

How to Fix Microsoft Project Custom Calendar Not Applying to a Task

Product: Microsoft Project
Device & OS: not provided
Scenario: Assigning a custom working time calendar to a specific project task to override standard working hours.
Observed behavior: The custom calendar does not take effect when selected, and reinstalling the software initially did not resolve the issue, though an automatic system update eventually fixed it.

Before you start

Ensure that your computer is connected to the internet to receive the latest Microsoft updates, and save your current project file to prevent any data loss during troubleshooting.

Solution 1Recommended

Install the Latest Microsoft Project Updates

Software bugs preventing custom calendars from applying correctly are often patched by Microsoft through automatic server updates.

In many cases, an unresponsive custom calendar is a known software glitch. Reinstalling the exact same version might not fix it, but installing the latest software patch provided by Microsoft will resolve the underlying bug.

Open Account Settings

Launch Microsoft Project. Click on 'File' in the top-left corner, then select 'Account' from the left-hand menu.

Check for Updates

Under the Product Information section, click on the 'Update Options' button.

Apply Updates

Select 'Update Now' from the drop-down menu. Wait for Microsoft Project to connect to the server, download, and apply any pending updates, then restart the application.

Install the Latest Microsoft Project Updates

Automatic Updates: If your organization manages your software updates, you may need to restart your computer or wait for your IT department to push the latest Office server updates to your machine.

Solution 2

Verify Task Calendar Settings in the Advanced Tab

Ensure the custom calendar is properly selected for the specific task and not being overridden by default resource schedules.

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Frequently Asked Questions

Why is my custom calendar not showing up in the task calendar list in Microsoft Project?

You may not have saved the calendar correctly. Go to Project > Change Working Time, ensure you clicked 'OK' after creating the new base calendar, and check if it was created for the current project file rather than just as a local template.

What does 'Scheduling ignores resource calendars' mean?

When this option is checked in the Advanced tab, Microsoft Project schedules the task strictly according to the assigned Task Calendar, disregarding any specific working times, shifts, or vacations set for the individual resources assigned to that task.

How do I create a new custom calendar in Microsoft Project?

Navigate to the Project tab on the ribbon, click on 'Change Working Time', and select 'Create New Calendar'. From there, you can define your specific working hours, shifts, and exception days (like holidays) before applying it to your tasks.

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