To unsubscribe everyone using Mass Removal, you’ll need to have the list of addresses that you want to unsubscribe. You can either paste this list of addresses (one address per line) within the menu box within the Mailman Administrator Portal.

Alternatively if you went through and obtained a list of users from the steps above. You can attach the list as either a .txt or .csv file. If a .txt file, then each user needs to be on a new row. With .csv files, Mailman will ignore the first record as it thinks it is the heading.
- Within the admin portal of Mailman, go to Membership Management … > Mass Removal.
- Note the options regarding whether or not to send a notification.
- Either paste the list of addresses into the dialog box (one email address per line) or click on Choose File and find the cleaned-up .txt file you saved.
- Click Submit Your Changes.
- You should get a confirmation email that the addresses have been unsubscribed.
- If you want to double-check, you can click on Membership Management to see a list of all members.
By default, list administrators are not automatically retained or added to a list. You may want to double-check within the admin portal that your list's owners are also listed as members under "Membership Management."