If you have several usernames in each ro

If you have several usernames in each role, you could try to narrow down the invalid user name by role rather than by user name. Highlight the users in a role and copy. Click the Add button and paste the copied list in the box. Click Check Names and the invalid name should be displayed in a prompt. If there are no invalid names in the current role, all names are verified. At least this can help you work role by role rather than one name at a time. Hope this helps.