How do I update shared mailbox time zone settings in Exchange Online?



Currently, shared mailbox time zone cannot be adjusted via the typical OWA process. If you navigate to the mailbox and then open mailbox options, the regional settings (in the General section) will give you a generic error.

Not having these settings match your organization's location will lead to calendar confusion when setting up meetings using shared calendars, as meetings created on the calendar will use the calendar's time zone, and meeting invites sent from it will be converted to local time zones of recipients.

This will cause issues for scheduling - for example, when you set up a meeting for 9am in the shared calendar, it will be set in PST, and those invited to it will see it in as starting at 6am (if their local time zone is EST).


You should verify two settings to make sure your mailbox and calendar regional settings match requirements.

  1. General mailbox regional settings
  2. Mailbox calendar working hours time zone settings

Setting the first value will not change the second, and vice versa.

General mailbox regional settings

You can use PowerShell to set shared mailbox regional settings. Run Microsoft Azure PowerShell as Administrator, and connect to your Exchange Online tenant (References section below provides a link to additional information on how to do that).

Once connected, verify regional settings for the mailbox:

get-mailboxregionalconfiguration [mailbox_alias]

In the screenshot above, it shows that none of the values are actually set.

Now we'll set those values:

set-mailboxregionalconfiguration [mailbox_alias] -dateformat 'M/d/yyyy' -timeformat 'h:mm tt' -language 'en-US' -timezone 'Eastern Standard Time'

The -timezone parameter accepts standard time zone classifications, such as 'Eastern Time Zone' or 'Pacific Time Zone'

Mailbox calendar working hours time zone settings

The second - and, arguably, even more important setting - is the working hours time zone settings for the mailbox calendar.

Run the following PowerShell command to see mailbox calendar settings:

get-mailboxcalendarconfiguration [mailbox_alias] | fl

Notice that even though we set mailbox regional settings to Eastern Standard Time, the calendar's WorkingHoursTimeZone still says Pacific Standard Time.

Assuming the correct time zone for this calendar is EST, fix the issue by running this PowerShell command:

set-mailboxcalendarconfiguration [mailbox_alias] -workinghourstimezone 'Eastern Standard Time'

That's it. Now scheduled meetings will correctly reflect the local time zone!


#exchangeonline #sharedcalendar #sharedmailbox #powershell #office365


Have more questions? Submit a request


Powered by Zendesk