New-MailUser

The Alias parameter specifies the Exchange alias (also known as the mail nickname) for the recipient. This value identifies the recipient as a mail-enabled object, and shouldn't be confused with multiple email addresses for the same recipient (also known as proxy addresses). A recipient can have only one Alias value. The maximum length is 64 characters.

The Alias value can contain letters, numbers and the following characters:

• !, #, %, *, +, -, /, =, ?, ^, _, and ~.
• $, &, ', `, {, }, and | need to be escaped (for example -Alias what`'snew) or the entire value enclosed in single quotation marks (for example, -Alias 'what'snew'). The & character is not supported in the Alias value for Microsoft Entra Connect synchronization.
• Periods (.) must be surrounded by other valid characters (for example, help.desk).
• Unicode characters U+00A1 to U+00FF.

When you create a recipient without specifying an email address, the Alias value you specify is used to generate the primary email address (alias@domain). Supported Unicode characters are mapped to best-fit US-ASCII text characters. For example, U+00F6 (ö) is changed to oe in the primary email address.

If you don't use the Alias parameter when you create a recipient, the value of a different required parameter is used for the Alias property value:

• Recipients with user accounts (for example, user mailboxes, and mail users): The left side of the MicrosoftOnlineServicesID or UserPrincipalName parameter is used. For example, helpdesk@contoso.onmicrosoft.com results in the Alias property value helpdesk.
• Recipients without user accounts (for example, room mailboxes, mail contacts, and distribution groups): The value of the Name parameter is used. Spaces are removed and unsupported characters are converted to question marks (?).

If you modify the Alias value of an existing recipient, the primary email address is automatically updated only in environments where the recipient is subject to email address policies (the EmailAddressPolicyEnabled property is True for the recipient).

The Alias parameter never generates or updates the primary email address of a mail contact or a mail user.

This parameter is available only in on-premises Exchange.

The ArbitrationMailbox parameter specifies the arbitration mailbox that's used to manage the moderation process for this recipient. You can use any value that uniquely identifies the arbitration mailbox. For example:

• Name
• Alias
• Distinguished name (DN)
• Canonical DN
• Domain\Username
• Email address
• GUID
• LegacyExchangeDN
• SamAccountName
• User ID or user principal name (UPN)

The Confirm switch specifies whether to show or hide the confirmation prompt. How this switch affects the cmdlet depends on if the cmdlet requires confirmation before proceeding.

• Destructive cmdlets (for example, Remove-* cmdlets) have a built-in pause that forces you to acknowledge the command before proceeding. For these cmdlets, you can skip the confirmation prompt by using this exact syntax: -Confirm:$false.
• Most other cmdlets (for example, New-* and Set-* cmdlets) don't have a built-in pause. For these cmdlets, specifying the Confirm switch without a value introduces a pause that forces you acknowledge the command before proceeding.

The DisplayName parameter specifies the display name of the mail user. The display name is visible in the Exchange admin center, in address lists, and in Outlook. The maximum length is 256 characters. If the value contains spaces, enclose the value in quotation marks (").

If you don't use the DisplayName parameter, the value of the Name parameter is used for the display name.

This parameter is available only in on-premises Exchange.

The DomainController parameter specifies the domain controller that's used by this cmdlet to read data from or write data to Active Directory. You identify the domain controller by its fully qualified domain name (FQDN). For example, dc01.contoso.com.

The ExternalEmailAddress parameter specifies the target email address of the mail contact or mail user. By default, this value is used as the primary email address of the mail contact or mail user.

In on-premises environments, you can use the PrimarySMTPAddress parameter to set the primary email address to a different value. However, we recommend this only in cross-forest environments.

This parameter is available only in the cloud-based service.

The FederatedIdentity parameter associates an on-premises Active Directory user with a user in the cloud.

The FirstName parameter specifies the user's first name.

The ImmutableId parameter is used by GAL synchronization (GALSync) and specifies a unique and immutable identifier in the form of an SMTP address for an Exchange mailbox used for federated delegation when requesting Security Assertion Markup Language (SAML) tokens. If federation is configured for this mailbox and you don't set this parameter when you create the mailbox, Exchange creates the value for the immutable ID based upon the mailbox's ExchangeGUID and the federated account namespace, for example, 7a78e7c8-620e-4d85-99d3-c90d90f29699@mail.contoso.com.

You need to set the ImmutableId parameter if Active Directory Federation Services (AD FS) is deployed to allow single sign-on into an off-premises mailbox and AD FS is configured to use a different attribute than ExchangeGUID for sign-on token requests. Both, Exchange and AD FS must request the same token for the same user to ensure proper functionality for a cross-premises Exchange deployment scenario.

The Initials parameter specifies the user's middle initials.

The LastName parameter specifies the user's last name.

This parameter is available only in the cloud-based service.

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The MacAttachmentFormat parameter specifies the Apple Macintosh operating system attachment format to use for messages sent to the mail contact or mail user. Valid values are:

• BinHex (This is the default value)
• UuEncode
• AppleSingle
• AppleDouble

The MacAttachmentFormat and MessageFormat parameters are interdependent:

• MessageFormat is Text: MacAttachmentFormat can be BinHex or UuEncode.
• MessageFormat is Mime: MacAttachmentFormat can be BinHex, AppleSingle, or AppleDouble.

This parameter is available only in the cloud-based service

This parameter is reserved for internal Microsoft use.

The MessageBodyFormat parameter specifies the message body format for messages sent to the mail contact or mail user. Valid values are:

• Text
• Html
• TextAndHtml (This is the default value)

The MessageFormat and MessageBodyFormat parameters are interdependent:

• MessageFormat is Mime: MessageBodyFormat can be Text, Html, or TextAndHtml.
• MessageFormat is Text: MessageBodyFormat can only be Text.

The MessageFormat parameter specifies the message format for messages sent to the mail contact or mail user. Valid values are:

• Text
• Mime (This is the default value)

The MessageFormat and MessageBodyFormat parameters are interdependent:

• MessageFormat is Mime: MessageBodyFormat can be Text, Html, or TextAndHtml.
• MessageFormat is Text: MessageBodyFormat can only be Text.

Therefore, if you want to change the MessageFormat parameter from Mime to Text, you must also change the MessageBodyFormat parameter to Text.

The MicrosoftOnlineServicesID parameter specifies the user ID for the object. This parameter only applies to objects in the cloud-based service. It isn't available for on-premises deployments.

The ModeratedBy parameter specifies one or more moderators for this recipient. A moderator approves messages sent to the recipient before the messages are delivered. A moderator must be a mailbox, mail user, or mail contact in your organization. You can use any value that uniquely identifies the moderator. For example:

• Name
• Alias
• Distinguished name (DN)
• Canonical DN
• Email address
• GUID

You can enter multiple values separated by commas. If the values contain spaces or otherwise require quotation marks, use the following syntax: "Value1","Value2",..."ValueN".

You need to use this parameter to specify at least one moderator when you set the ModerationEnabled parameter to the value $true.

The ModerationEnabled parameter specifies whether moderation is enabled for this recipient. Valid value are:

• $true: Moderation is enabled for this recipient. Messages sent to this recipient must be approved by a moderator before the messages are delivered.
• $false: Moderation is disabled for this recipient. Messages sent to this recipient are delivered without the approval of a moderator. This is the default value.

You use the ModeratedBy parameter to specify the moderators.

The Name parameter specifies the unique name of the mail user. The maximum length is 64 characters. If the value contains spaces, enclose the value in quotation marks (").

This value is also used for the DisplayName property if you don't use the DisplayName parameter.

The OrganizationalUnit parameter specifies the location in Active Directory where the new mail user is created.

Valid input for this parameter is an organizational unit (OU) or domain that's returned by the Get-OrganizationalUnit cmdlet. You can use any value that uniquely identifies the OU or domain. For example:

• Name
• Canonical name
• Distinguished name (DN)
• GUID

The Password parameter specifies the password for the user's account.

You can use the following methods as a value for this parameter:

• (ConvertTo-SecureString -String '<password>' -AsPlainText -Force).
• Before you run this command, store the password as a variable (for example, $password = Read-Host "Enter password" -AsSecureString), and then use the variable ($password) for the value.
• (Get-Credential).password to be prompted to enter the password securely when you run this command.

This parameter is functional only in on-premises Exchange.

The PrimarySmtpAddress parameter specifies the primary return email address that's used for the recipient.

By default, the primary address is the same as the ExternalEmailAddress parameter value.

If you use the PrimarySmtpAddress parameter to specify the primary email address, the command sets the EmailAddressPolicyEnabled property of the mail user to False, which means the email addresses of the mail user aren't automatically updated by email address policies. We recommend that you don't set the primary email address to a value other than the ExternalEmailAddress unless you're in a cross-forest scenario.

The RemotePowerShellEnabled parameter specifies whether the user can connect to Exchange using remote PowerShell. Remote PowerShell is required to open the Exchange Management Shell on Exchange servers, or to use Windows PowerShell open and import a remote PowerShell session to Exchange. Access to remote PowerShell is required even if you're trying to open the Exchange Management Shell on the local Exchange server. Valid values are:

• $true: The user can use remote PowerShell. This is the default value.
• $false: The user can't use remote PowerShell.

This parameter is available only in on-premises Exchange.

The ResetPasswordOnNextLogon parameter specifies whether the user must change their password the next time they log on. Valid values are:

• $true: The user is required to change their password the next time they log on.
• $false: The user isn't required to change their password the next time they log on. This is the default value.

This parameter is available only in on-premises Exchange.

The SamAccountName parameter (also known as the pre-Windows 2000 user account or group name) specifies an object identifier that's compatible with older versions of Microsoft Windows client and server operating systems. The value can contain letters, numbers, spaces, periods (.), and the following characters: !, #, $, %, ^, &, -, _, {, }, and ~. The last character can't be a period. Unicode characters are allowed, but accented characters may generate collisions (for example, o and ö match). The maximum length is 20 characters.

The SendModerationNotifications parameter specifies when moderation notification messages are sent. Valid values are:

• Always: Notify all senders when their messages aren't approved. This is the default value.
• Internal: Notify senders in the organization when their messages aren't approved.
• Never: Don't notify anyone when a message isn't approved.

This parameter is only meaningful when moderation is enabled (the ModerationEnabled parameter has the value $true).

The UsePreferMessageFormat specifies whether the message format settings configured for the mail user or mail contact override the global settings configured for the remote domain or configured by the message sender. Valid value are:

• $true: Messages sent to the mail user or mail contact use the message format that's configured for the mail user or mail contact.
• $false: Messages sent to the mail user or mail contact use the message format that's configured for the remote domain (the default remote domain or a specific remote domain) or configured by the message sender. This is the default value.

This parameter is available only in on-premises Exchange.

The UserPrincipalName parameter specifies the name of a system user in an email address format (for example, ed@contoso.com).

The WhatIf switch simulates the actions of the command. You can use this switch to view the changes that would occur without actually applying those changes. You don't need to specify a value with this switch.