Calendar Problems

How to Fix Incorrect Room Resource Working Hours in Microsoft 365

Maira Mehtab Sep 22, 2026 869 views

Question details

Users need to resolve an issue where room resource calendars show incorrect working hours or appear grayed out during normal business hours.

Product: Microsoft 365
Device & OS: not provided
Scenario: Scheduling meetings and managing room resource availability in the Microsoft 365 calendar.
Observed behavior: The room resource availability calendar shows working hours outside the configured schedule or grays out entirely during normal working hours, despite correct time zone and language settings.

Before you start

Verify whether you have Microsoft 365 administrator privileges, as resolving backend sync issues for room resources requires access to the admin center.

Solution 1Recommended

Verify Mailbox Settings and Contact Microsoft Support

Check your base mailbox configurations and escalate the backend issue to Microsoft through an administrative service request.

Because this behavior often persists even when local configurations are correct, it is highly likely to be a service-side error. Checking the basic parameters is required before submitting a ticket to the Microsoft backend.

Verify Room Settings

Double-check the room mailbox configurations to ensure that the time zone, language, working days, and working hours are set correctly.

Log in to the Admin Center

If you are a Microsoft 365 administrator, navigate to https://admin.microsoft.com/ and log in with your administrative credentials.

Create a Service Request

Go to the Support section in the Microsoft 365 admin center and create a new service request describing the room resource calendar error.

Contact Your Organization's IT

If you do not have administrative privileges, contact your internal IT department or organization administrator so they can open the support ticket on your behalf.

Backend Service Issue: This specific calendar display error is not currently listed as a known client-side issue and typically requires intervention from the Microsoft service backend.

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Frequently Asked Questions

Why is my Microsoft 365 room calendar grayed out during working hours?

This usually happens due to a mismatch in the room's time zone settings or a service-side backend issue in Microsoft 365. Verifying the mailbox regional settings is the first step before contacting support.

How can I check the working hours for a room resource?

An administrator can check and adjust the working hours through the Microsoft 365 admin center under the resource's booking options, or by using Exchange PowerShell cmdlets like Get-MailboxCalendarConfiguration.

Do I need administrator rights to fix room resource calendar issues?

Yes. While standard users can view the grayed-out calendar, changing room mailbox settings or submitting a backend support ticket to Microsoft requires Microsoft 365 administrator privileges.

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