Steps:
Case 1:
> We are create one user with "Other" Type.
E.g., Username: yogesh
> We are create user through import users screen with updating username of "yogesh" which is already created through other type.
> same username are created multiple time.

Case 2:
> We are create one user with "Other" type.
E.g.,Username:abhinav@occucare.co.in
> Now go to manage employee login and select one record for adding mail id and click on "Set EmailId as User Name" and user are created.
> same username are created multiple time.