Exchange 2010 seems to have a bug in that you are unable to make changes to the default email policy using the EMC. Doing so results in an error: “The operation can’t be performed on the default policy”.
Copy pasting the cmdlet show into EMS gives an error too.
The problem is simple. Being the default policy it does not let you do things like set conditional attributes or set a Recipient Container OU or even change the name; so even though you are not really changing any of these in the PowerShell cmdlet the mere fact that you are specifying them with their default values is not allowed.
The solution too is simple. Copy paste the cmdlet into EMS, remvoe all the
-Name switches and presto your cmdlet works! In my case, for the example in the screenshot, here’s the cmdlet I finally ran:
set-EmailAddressPolicy -EnabledEmailAddressTemplates 'SMTP:%firstname.lastname@example.org','smtp:%email@example.com' -Identity 'Default Policy'
Note to self: Only one of the email address templates is allowed the prefix SMTP in all-caps. The others must have SMTP in lower case. The one with the SMTP in all-caps is the primary email address template.