Setting the EwsAllowMacOutlook property to "false" does not block Outlook for Mac

Symptoms

Consider the following scenario:

• The EwsEnabled property is not set at both the organization level and the mailbox level in Microsoft Exchange Server 2013.

• You run one of the following cmdlets to disable Microsoft Outlook for Mac access to the Exchange server:

  • Set-OrganizationConfig –EwsAllowMacOutlook False

  • Set-CASMailbox –identity <user mailbox> –EwsAllowMacOutlook False

In this situation, Outlook for Mac users can still access the Exchange server.

Cause

If the EwsEnabled property is not set at both the mailbox and organization levels, then it has the default NULL value. Therefore, the Exchange server assumes users are allowed to access the server, and it will not check other settings such as the EwsAllowMacOutlook property.

Resolution

To resolve this issue, follow these step to set the EwsEnabled and EwsAllowMacOutlook properties:

1. Open Exchange Management Shell.

2. Run the following cmdlet to set the EwsEnabled property to either "True" or "False" as appropriate for your organization:Set-OrganizationConfig -EwsEnabled $True (or $False)

3. Use the following cmdlet to change the value for each user who has a different requirement:Set-CASMailbox < Alias > -EwsEnabled $False (or $True)

4. Use one of the following cmdlets to set the EwsAllowMacOutlook property accordingly:
   
   For a user mailboxSet-CASMailbox < Alias > -EwsAllowMacOutlook $False (or $True) For the organizationSet-OrganizationConfig -EwsAllowMacOutlook $False (or $True)

For more information about the Set-OrganizationConfig cmdlet, see Set-OrganizationConfig.