Hi there,
I have an additional alias to add to 100’s of user accounts in O365. I was hoping to add these to a .csv file and use powershell to add these.
I don’t require these to be primary addresses but just to act as an additional address.
Does anyone know the command to put into Powershell at all? I was provided with one:
$csv = import-csv file.csv
foreach($users in $csv)
{
set-mailbox $emailaddress -emailaddresses @{add=“$secondaryemailaddress”}
}
When I run this it displays the error message
Cannot process argument transformation on parameter ‘EmailAddresses’. Cannot convert value “System.Collections.Hashtable” to type “Microsoft.Exchange.Data.ProxyAddressCollection”.
What are the values of $EmailAddress and $SecondaryEmailAddress, and where are you populating them? If the only code you’re running is what’s in the example above, then these values will be null.
Need to see the headers of your csv file. I expect it needs to be something like:
set-mailbox $users.emailaddress -emailaddresses @{add=“$($users.secondaryemailaddress)”}
Also, don’t run this or anything else on your whole list as a test. Edit your csv file to just one user, that way, you only have 1 user to fix if it makes a mess.
Hi Matt & Ron,
Apologies if my first post wasn’t the best. Fairly new to Powershell so slowly getting to grips with it all.
Thankfully I am only testing this on one user so that I don’t mess up the entire tenant! I basically have a spreadsheet with 3 columns titled:
users - the contains the users full name
emailaddress - this contains the users primary smtp address
secondaryemailaddress - this contains the email address that I would like to add as an additional alias.
Not sure if this is what you’re after but please let me know if not.
I guessed right then, try substituting my line for set-mailbox and see if it works. Just make a note of what’s currently there so you can fix it.
Ron, why you suggect use @{add=“$($users.secondaryemailaddress)”}
instead of @{ add = $users.secondaryemailaddress } ?
It will spread over internet and get rise to dozens of new wuestions 
Hi All,
Thanks for your replies.
I managed to get this working in the end using the following:
Import-CSV “.\MultipleAlias.csv” | ForEach {Set-Mailbox $.Mailbox -EmailAddresses @{add=$.NewEmailAddress}}