Multiple mailboxes in Microsoft Office 365 may have incorrect or missing time zone settings. This symptom applies to all kinds of mailboxes, such as user mailboxes, resource mailboxes, and equipment mailboxes.


To resolve this issue, bulk change the time zone info for mailboxes in Office 365. To do this, follow these steps:

  1. Connect to Exchange Online by using remote PowerShell. For more info about how to do this, go to the following Microsoft website:

    Connect to Exchange Online Using Remote PowerShell

  2. Run the following Windows PowerShell commands:

    1. $users = Get-Mailbox –ResultSize unlimited –Filter{(RecipientTypeDetails –eq 'RoomMailbox')} 
    2. $users | %{Set-MailboxRegionalConfiguration $_.Identity –TimeZone "Pacific Standard Time"} 


    • You can replace "RoomMailbox" with another valid Exchange recipient type, such as "UserMailbox" or "EquipmentMailbox."

    • Replace "Pacific Standard Time" with the time zone that's appropriate for you.


For more info about the Set-MailboxRegionalConfiguration cmdlet, go to the following Microsoft TechNet website:


Still need help? Go to Microsoft Community.

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