How to Change Default Mailbox Language in Microsoft Outlook and Exchange

The easiest method for changing a single user's mailbox language is through the Outlook web interface. This method works for both Exchange Online and on-premises environments.

Sign in to Outlook on the web using your credentials. Once logged in, look for the three dots menu icon in the top navigation bar and click it.

From the dropdown menu, select Settings. This opens the basic settings panel. To access the full language configuration options, click View all Outlook settings at the bottom of the settings panel.

In the settings interface, navigate to General in the left sidebar, then click Language and time. Here you'll find the language dropdown menu where you can select your desired language from the available options.

Select your preferred language from the dropdown menu. Make sure to check the box labeled Rename default folders so their names match the specified language. This ensures that system folders like Inbox, Sent Items, and Drafts will be renamed to match your selected language.

Click Save to apply the changes. The language change takes effect immediately without requiring a restart of Outlook.

For bulk operations or when you need to change language settings for multiple users, PowerShell provides a more efficient approach. First, you need to establish a connection to Exchange Online.

Open PowerShell as an administrator. You can do this by right-clicking on the PowerShell icon and selecting "Run as administrator".

Connect to Exchange Online using the following command:

Connect-ExchangeOnline

This command will prompt you to sign in with your Microsoft 365 administrator credentials. Enter your credentials when prompted. The connection process may take a few moments to complete.

Once connected, you'll see a confirmation message indicating successful connection to Exchange Online. You can now run Exchange Online PowerShell cmdlets.

Get-OrganizationConfig | Select-Object Name

This should return your organization's name, confirming the connection is active.

Once connected to Exchange Online, you can change the mailbox language for individual users using the Set-MailboxRegionalConfiguration cmdlet.

Use the following command structure to change language settings for a single user:

Set-MailboxRegionalConfiguration -Identity "user@domain.com" -Language "language-code" -LocalizeDefaultFolderName -DateFormat "d-M-yyyy" -TimeFormat "HH:mm"

Here's a practical example changing a user's language to Dutch:

Set-MailboxRegionalConfiguration -Identity "anne.green@company.com" -Language "nl-NL" -LocalizeDefaultFolderName -DateFormat "d-M-yyyy" -TimeFormat "HH:mm"

The -LocalizeDefaultFolderName parameter ensures that default folders (Inbox, Sent Items, Drafts, etc.) are renamed to match the specified language. The -DateFormat and -TimeFormat parameters set the regional date and time display formats.

Common language codes include:

• nl-NL for Dutch (Netherlands)
• de-DE for German (Germany)
• pt-BR for Portuguese (Brazil)
• da-DK for Danish (Denmark)
• ja-JP for Japanese (Japan)
• fr-FR for French (France)
• es-ES for Spanish (Spain)

Get-MailboxRegionalConfiguration "anne.green@company.com"

When you need to change language settings for multiple users or your entire organization, PowerShell provides efficient bulk operations.

To change the language for all mailboxes in your organization, use this command:

Get-Mailbox -ResultSize Unlimited | Set-MailboxRegionalConfiguration -Language "nl-NL" -LocalizeDefaultFolderName -DateFormat "d-M-yyyy" -TimeFormat "HH:mm"

This command retrieves all mailboxes and applies the language change to each one. The -ResultSize Unlimited parameter ensures all mailboxes are included, not just the default 1000.

For more targeted bulk operations, you can filter specific users. For example, to change language only for users in a specific department:

Get-Mailbox -Filter "Department -eq 'Sales'" | Set-MailboxRegionalConfiguration -Language "de-DE" -LocalizeDefaultFolderName

If you have a CSV file with specific users to update, you can process them in batch:

$users = Import-CSV "C:\temp\users.csv" -Encoding UTF8
Foreach($user in $users) {
    Set-MailboxRegionalConfiguration -Identity $user.Email -Language "de-DE" -DateFormat $null -TimeFormat $null -LocalizeDefaultFolderName
}

Your CSV file should have a column named "Email" containing the user email addresses.

Get-Mailbox -ResultSize 5 | Get-MailboxRegionalConfiguration | Select-Object Identity, Language

For Exchange on-premises environments, the process is similar but uses the Exchange Management Shell instead of connecting to Exchange Online.

Open the Exchange Management Shell as an administrator. You can find this in the Microsoft Exchange Server program group in your Start menu.

The Exchange Management Shell automatically loads the necessary Exchange cmdlets and connects to your local Exchange server. No additional connection command is required.

Use the same Set-MailboxRegionalConfiguration cmdlet for on-premises environments:

Set-MailboxRegionalConfiguration -Identity "DOMAIN\username" -Language "nl-NL" -LocalizeDefaultFolderName -DateFormat "d-M-yyyy" -TimeFormat "HH:mm"

Note that for on-premises Exchange, you can use either the email address or the domain\username format for the Identity parameter.

For bulk operations on-premises, the commands are identical to Exchange Online:

Get-Mailbox -Server "ExchangeServer01" | Set-MailboxRegionalConfiguration -Language "de-DE" -LocalizeDefaultFolderName

You can specify a particular Exchange server using the -Server parameter if you have multiple servers in your environment.

Get-MailboxRegionalConfiguration "DOMAIN\username"

Sometimes language changes don't appear immediately or folder names don't update as expected. Here are the most common issues and their solutions.

If the language change isn't visible in Outlook after making the change, the user doesn't need to restart Outlook as changes should apply immediately. However, if the change doesn't appear, you can force an update using Outlook command line parameters.

Open Command Prompt or PowerShell and run:

outlook.exe /resetfolders

Or specifically for folder names:

outlook.exe /resetfoldernames

These commands force Outlook to refresh the folder structure and apply the new language settings.

If folder names still aren't updating after using PowerShell with the -LocalizeDefaultFolderName parameter, verify that this parameter was included in your command. Without it, only the interface language changes, but folder names remain in their original language.

For users who had their preferred language already selected but folders weren't localized, try this workaround through the web interface: select a different language, save the settings, then switch back to the preferred language and save again. This forces a complete refresh of the language settings.

If you encounter permission errors when running PowerShell commands, ensure your account has the necessary Exchange administrative roles. For Exchange Online, you need Exchange Administrator or Global Administrator permissions. For on-premises, you need Exchange Organization Management or Recipient Management permissions.

Get-MailboxRegionalConfiguration "user@domain.com" | Format-List

This displays all regional configuration details including Language, DateFormat, TimeFormat, and TimeZone.