Hi, Brian,

These commands work for 1 account at a time. If you’re trying to update multiple users accounts from a TXT file all at once you have to use a Powershell script.

Your import file should look like this:
Name, ProxyAddresses
user1, email1;email2;email3;email4
user2, email1;email2;email3… etc

Create a new TXT file with the following content (make sure to update the location of your import file):

Import-Csv C:\alias.csv | ForEach-Object{
$name = $_.Name
$proxy = $_.ProxyAddresses -split ‘;’
Set-Mailbox -Identity $name -EmailAddresses @{add= $proxy}
}

Save the txt file as import-alias.ps1 (a powershell script file) and run the script within Powershell by typing c:\import-aslias.ps1

This will run the three commands for each line in the c:\alias.csv file.

Just remember that these commands will REPLACE all addresses on an account, no append.

Let me know how this works for you.
Jonathan