If you wish to delete a user you must first remove any Active projects they have access to, you can easily see if a user has active projects as their name will be highlighted green in the user list,
Click the pencil icon, select the active projects tab and then either delete each project individually or use the batch delete tools.
Once you have removed the user from projects you can delete the user.
Note: Using the delete tools in the user profile does not delete the actual projects only the users access.
