Applies to: Exchange Online

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

Use the Set-LinkedUser cmdlet to modify the properties of an existing linked user account. The Outlook Live Directory Sync (OLSync) service account is a linked user.

For information about the parameter sets in the Syntax section below, see Syntax.

Set-LinkedUser -Identity <UserIdParameter> [-CertificateSubject <MultiValuedProperty>] [-Confirm [<SwitchParameter>]] [-WhatIf [<SwitchParameter>]]

This example modifies the certificate subject for the linked user "GALSync-ServiceAccount".

Set-LinkedUser "GALSync-ServiceAccount" -CertificateSubject "X509:<I><S>C=US,O=Contoso Corp,"

The OLSync service account is the only linked user in your organization. By default, the account is named GALSync-ServiceAccount.

You need to be assigned permissions before you can run this cmdlet. Although all parameters for this cmdlet are listed in this topic, you may not have access to some parameters if they're not included in the permissions assigned to you. To see what permissions you need, see the "Linked user" entry in the Feature permissions in Exchange Online topic.


Parameter Required Type Description




The Identity parameter specifies the linked user. You can use any value that uniquely identifies the linked user, for example:

  • Name

  • Distinguished name (DN)




The CertificateSubject parameter specifies the value of the subject field of the user's digital certificate. The syntax of the CertificateSubject value is X509:<I>Issuer<S>Subject. The values of Issuer and Subject are required and must be in X.500 format. To remove the value of CertificateSubject, specify the value $null.




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 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.

To see the input types that this cmdlet accepts, see Cmdlet Input and Output Types. If the Input Type field for a cmdlet is blank, the cmdlet doesn’t accept input data.

To see the return types, which are also known as output types, that this cmdlet accepts, see Cmdlet Input and Output Types. If the Output Type field is blank, the cmdlet doesn’t return data.