How to hydrate user accounts in OWA to avoid warning or error in Signature Manager Office 365 Edition


In Signature Manager Office 365 Edition, the following warning/error is displayed:

The user must sign in to OWA at least once to create the mailbox so that the signature and settings can be applied


For Signature Manager Office 365 Edition to deploy signatures and settings to a user’s OWA account (for either Exchange or Office 365), the user’s profile must have been created in OWA. This is known as ‘hydrating’ a user’s account.

A user’s profile is hydrated the first time they log on to OWA and select their regional options. It is not hydrated when a user accesses their mailbox using an email client such as Outlook - they must log on to the OWA website itself for the mailbox to be hydrated.


To avoid the need for all users to log on to the OWA website so their signatures are deployed, you can use PowerShell commands to hydrate a user’s profile. To do this, follow the steps below:

  1. Run Windows Powershell.
  2. Use the command below to check your execution policy settings:

  3. Get-ExecutionPolicy    
    If the execution policy is set to Restricted, change it to RemoteSigned or Unrestricted using the command below:

    Set-ExecutionPolicy RemoteSigned    

  4. Provide Office 365 Global Administrator credentials using the command below:

  5. $LiveCred = Get-Credential    

  6. To connect to Exchange Online (Office 365):

  7. $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri -Credential $LiveCred -Authentication Basic -AllowRedirection    

  8. Start the connection using the command below:

  9. Import-PSSession $Session    

  10. Once connected, run the following command to hydrate a user’s mailboxes:

  11. Get-Mailbox <user> | Set-MailboxRegionalConfiguration -TimeZone "<Time Zone>" –Language <Language>  -DateFormat "<Date Format>"    

    Replace <user> with the user’s account, <Time Zone> with the user’s time zone name, <Language> with the Language Culture Name, and <Date Format> with the required date format (retain quotes where shown).

    For example, for a user in the UK:

    Get-Mailbox | Set-MailboxRegionalConfiguration -TimeZone "GMT Standard Time" –Language en-GB  -DateFormat "dd/MM/yyyy"    

    For example, for a user in the US Central time zone:

    Get-Mailbox | Set-MailboxRegionalConfiguration -TimeZone "Central Standard Time" –Language en-US  -DateFormat "MM/dd/yyyy"    


Commands detailed in step 2 above show how to a hydrate mailboxes for specified users. However, if required you can hydrate mailboxes for all users, using the command below:

Get-Mailbox -ResultSize unlimited | Set-MailboxRegionalConfiguration -TimeZone "<Time Zone>" –Language <Language> -DateFormat "<Date Format>"

For example, if all of your users are in the UK, you can use the command below to hydrate all users’ mailboxes:

Get-Mailbox -ResultSize unlimited | Set-MailboxRegionalConfiguration -TimeZone "GMT Standard Time" –Language en-GB  -DateFormat "dd/MM/yyyy"

If you have users in multiple different time zones, or that require different language options, you can use other input parameters available for the Get-Mailboxcmdlet to apply settings to a group or subset of users.

Signature Manager Outlook Edition Signature Manager Office 365 Edition Troubleshooting