Error: The name supplied already exists. Another customer, supplier, or employee is already using this name
The error "The name supplied already exists. Another customer, supplier, supplier or employee is already using this name" is usually caused by one of the following:
Importing Data from QuickBooks Desktop or turning on payroll after adding employees in QuickBooks Online.
The customer, supplier, or employee name you are trying to add already exists in QuickBooks Online.
Change the display name
Here's how to change the display name:
Log in to your QuickBooks Online company file.
Select Expenses and then Suppliers.
Select the name of the duplicate supplier.
Select Edit under the Toolbar. (Note: Select Sales and then Customers if you are doing this to check for duplicates in your Customer List.)
Change the Display name as format, to "last, first."
Editing the duplicate or making it inactive
If you continue to get the error, there may be more than one duplicate. You can choose to edit the duplicate, or make it inactive (if no longer needed).
From the left menu, select Sales or Expenses or Workers, then choose Customers or Suppliers or Employees respectively.
Find the duplicate Supplier or Customer or Employee.
Select Edit under the Toolbar.
In the Display name as field, add a digit at the end of the name. (Note: If the profile is no longer in use, you can select Make inactive. Making the existing name inactive will also allow them to add the new, identical name.)