Sometimes when users want a distribution list then tend to copy people from an existing list and paste their entire addresses. Fx. Qweasd Rotkju <QWERT@Nortwind.com>. This is a no-go when pasting into the Members pane in Active Directory. It would be better to educate people not to do that, but it's not the quickest. Below is a simple way to remove everything except the "User logon name".
First I copy/paste everything into a txt file and save as test.csv. Then I open the file in Excel. Every address is listed in its own column. Then...
: Mark row 1 :
: Open Replace :
: Type *< and leave Replace With blank . This removes everything up to the user logon name :
: Then type @* and ; in Replace With . This removes everything after @ incl. the @ leaving only the user logon name but with a semi colon. AD likes this uuuhhmmmm yummy it'll chew right up....