Adding and removing extensionattribute to AD object - powershell

Question

I'm using powershell to modify some AD extensionattribute.
This is my code to add an extensionattribute
Set-ADUser -Identity "anyUser" -Add #{extensionAttribute4="myString"}
It works, but how can I remove the same extensionattribute? I can't find anything similar to -remove.

Answer 1

You could try using the -Clear parameter
Example:-Clear Attribute1LDAPDisplayName, Attribute2LDAPDisplayName
http://technet.microsoft.com/en-us/library/ee617215.aspx

Answer 2

I used the following today - It works!
Add a value to an extensionAttribute
$ThisUser = Get-ADUser -Identity $User -Properties extensionAttribute1
Set-ADUser –Identity $ThisUser -add #{"extensionattribute1"="MyString"}
Remove a value from an extensionAttribute
$ThisUser = Get-ADUser -Identity $User -Properties extensionAttribute1
Set-ADUser –Identity $ThisUser -Clear "extensionattribute1"

Answer 3

I have struggled a long time to modify the extension attributes in our domain.
Then I wrote a powershell script and created an editor with a GUI to set and remove extAttributes from an account.
If you like, you can take a look at it at http://toolbocks.de/viewtopic.php?f=3&t=4
I'm sorry, that the description in the text is in German. The GUI itself is in English.
I use this script on a regular basis in our domain and it never deleted anything or did any other harm. I provide no guarantee, that this script works as expected in your domain. But as I provide the source, you can (and should) have a look at it, before you run it.

Answer 4

Extension attributes are added by Exchange. According to this Technet article something like this should work:
Set-Mailbox -Identity "anyUser" -ExtensionCustomAttribute4 #{Remove="myString"}

Answer 5

Or the -Remove parameter
Set-ADUser -Identity anyUser -Remove #{extensionAttribute4="myString"}

Answer 6

To clear the value you can always reset it to $Null. For example:
Set-Mailbox -Identity "username" -CustomAttribute1 $Null

Answer 7

Set-ADUser -Identity anyUser -Replace #{extensionAttribute4="myString"}
This is also usefull