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(Global Admin) Room and User Working Hours / Outlook Calendar Availability

Lindsey Devillier 5 Reputation points
2025-12-08T06:56:10.4933333+00:00

Hey Everyone,

Thanks in advance for your help. Within the last two weeks, our working hours were changed tenant-wide which impacted the availability of users and room resources. All room resources are showing as unavailable regardless of the time selected unless we manually update the room availability via PowerShell.

What's strange is that a room resource will show as unavailable even though it is available. A user can book the room successfully despite being flagged as unavailable. To fix this, we've changed the room working hours in PowerShell. Ticking and unticking the box "Allow scheduling only during working hours" didn't change anything.

On our end, nothing was changed. Microsoft support has asked that we run PowerShell for each user and each room to change the working hours. It's unclear what the root cause of this issue is and according to Microsoft Support, there is no way to change this setting across the tenant.

Has anyone ever experienced this before? What's the cause? Most importantly, what's the most feasible solution?

Thank you all for your help.

Outlook | Web | Outlook on the web for business | Settings

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  1. Tina L 8,820 Reputation points Microsoft External Staff Moderator
    2025-12-08T10:31:34.9633333+00:00

    Hello @Lindsey Devillier, 

    Thank you for reaching out to the Q&A forum! 

    First of all, I understand that you’re looking to hear from others who may have experienced the same issue, so I’ll make sure this thread remains open for community members to share their insights. 

    I hope you understand that the Q&A forum has certain limitations in terms of tools, backend access, and troubleshooting capabilities.  

    So, for tenant-wide configuration issues like yours, I strongly recommend posting your question in the Microsoft Tech Community. That forum is actively monitored by moderators and technical experts who can provide deeper assistance and guidance. 

    User's image I apologize for redirecting you to a different community, but this will ensure you receive the most accurate and comprehensive support for your scenario. 

    In addition, based on what you’ve described, this issue likely requires backend investigation by the Microsoft Support ticket team. They have the necessary tools and permissions to check mailbox configurations, server synchronization, and other factors that could be causing the incorrect availability status.  

    Sometimes identifying the root cause can take time due to checks on service health and propagation across all mailboxes, so I appreciate your patience during this process. 

    Additionally, I've sent you a private message to help protect your personal information. Please take a moment to check it out.       

    Note: To access private message platform, please reload this thread page and select "View messages" as below screenshot.     

    User's image

    Looking forward to your reply.

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

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