Powershell setting Mailnickname attribute - powershell

Question

I have a bit of powershell code that after a user has been created the code assigns the account loads of attributes using Quest/AD. All the attributes assign except Mailnickname. Is there a reason for this / how can I fix it. Below is my code:
get-qaduser $xy | Add-QADProxyAddress -Address ("SMTP:"+$x) -verbose
get-qaduser $xy | Add-QADProxyAddress -Address ("SMTP:"+$xy+"#domainexample.mail.onmicrosoft.com") -verbose
get-qaduser $xy | Set-QADUser -ObjectAttributes #{msExchVersion="44210883383015"} -verbose
Set-QADUser -identity $xy -ObjectAttributes #{mailnickname = $xy}
Would anyone have any suggestions of what to / how to go about setting this.
Thanks in advance.
Steve

Answer 1

Do you have to use Quest? This works in PS v3 natively:
Get-ADUser $xy | Set-ADUser -Add #{mailNickname=$xy}
Or:
Get-ADUser $xy | Set-ADUser -Replace #{mailNickname=$xy}
Responding to your question below:
I assume you mean PowerShell v1. I haven't used PS v1. Are you starting your script with Import-Module ActiveDirectory? If not, you should post that at the top of your line. For Quest around here the script always starts with Import-Module ActiveDirectory and the next line is Add-PSSnapIn Quest.ActiveRoles.ADManagement. This would work in PS v2:
Import-Module ActiveDirectory
Add-PSSnapIn Quest.ActiveRoles.ADManagement
#This line lets you just type the user you want to modify
$XY = Read-Host "Input User ID"
#This is your code you said works
get-qaduser $xy | Add-QADProxyAddress -Address ("SMTP:"+$x) -verbose
get-qaduser $xy | Add-QADProxyAddress -Address ("SMTP:"+$xy+"#domainexample.mail.onmicrosoft.com") -verbose
get-qaduser $xy | Set-QADUser -ObjectAttributes #{msExchVersion="44210883383015"} -verbose
#This should add the mailNickname property through standard PS
Get-ADUser $XY | Set-ADUser -Add #{mailNickname = $XY}
See if that does what you need and get back to me. Remember: in this example you're declaring the variable $XY to be whatever the user inputs when running the script.

Answer 2

The likely reason you're seeing this is because of the ARS 'Built-in Policy - Default E-mail Alias' Policy. You can verify that this is the case by checking the change history for the user object(s) you're trying to create/modify.
You'll see Property 'Alias (mailNickName)' is removed from the operation request as no Exchange tasks were requested.
Try setting the targetAddress attribute at the same time to avoid being dropped by this policy.