How to Fix Ambiguous Parameter for Powershell Script

Question

I am trying to copy group membership from one user to another in AD using Powershell. I get the error below. Can't seem to figure it out.

Get-ADUser -server "test.server.com" -Identity user11 -Properties memberof |
Select-Object -ExpandProperty memberof
Add-ADGroupMember -Member user22 

The error I receive is

Add-ADGroupMember : Parameter cannot be processed because the parameter name 'Member' is ambiguous. Possible matches include:
-Members 
-MemberTimeToLive. At line:3 char:19
+ Add-ADGroupMember -Member user22
+                   ~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Add-ADGroupMember], ParameterBindingException
    + FullyQualifiedErrorId : AmbiguousParameter,Microsoft.ActiveDirectory.Management.Commands.AddADGroupMember

Answer 1

So lets talk about what the error Ambiguous means.

In Powershell you can write short hand

Get-ChildItems -path C:\Test

is the same as

Get-ChildItems -pat C:\Test

If we look at the documentation from Microsoft on Add-AdGroupMember

We can see that the command has 2 parameters with Member in it -MemberTimeToLive and -Members

What the error means is it doesnt know if -Member is you calling -Members or -MemberTimeToLive

This is called Ambiguous

The fix would be

Add-ADGroupMember -Members user22 

Answer 2

The error message is very clear. PowerShell does partial matching of parameter names, and will accept a partial parameter name if it is sufficient to be uniquely identifiable. In your case, the partial parameter -Member does not match uniquely; it could be referring to either -Members or -MemberTimeToLive. To fix it, you should use -Members instead of -Member.