Do you have one or more mailboxes running in a wrong TimeZone on your Office 365 or Exchange environment? Don't worry it is easy to fix, and I will show you how do to it. Follow this blog post and you will learn how to see current TimeZone on a mailbox, how to change it, and how to changes TimeZone on all mailboxes.

See current TimeZone on a mailbox
To see current TimeZone on a mailbox, simply use this command.

Get-MailboxRegionalConfiguration -Identity user@domain.com

Change TimeZone on one mailbox

To change the TimeZone on a mailbox we need to use Set-MailboxRegionalConfiguration like below.

Set-MailboxRegionalConfiguration -Identity user@domain.com -TimeZone "Romance Standard Time"

Change TimeZone on all mailboxes

You can use following PowerShell command to change the TimeZone on all mailboxes.

Get-Mailbox -ResultSize unlimited -Filter {RecipientTypeDetails -eq 'UserMailbox'} | Set-MailboxRegionalConfiguration -TimeZone "Romance Standard Time"

TimeZones

Not sure which TimeZone to use? Please see the TimeZone tabel on Microsoft's website (http://technet.microsoft.com/en-us/library/cc749073(WS.10).aspx).