When a new Exchange Online mailbox is created the user is prompted to set language and time zone at first logon. This information is possible to pre-populate to make the experience smoother for the end users. This is particularly useful in a migration scenario.

These settings are set with the cmdlet Set-MailboxRegionalConfiguration.

Example:

Set-MailboxRegionalConfiguration -identity "aaron.beverly@365lab.net" `
    -TimeZone "W. Europe Standard Time" -Language "sv-SE" -confirm:$false

Some useful links:

• Microsoft Time Zone Index Values
• Table of Language Culture Names

/ Andreas