Resolving "The name _____ of the list element is already in use" sync error.

This error is fairly common and easy to fix. Take these steps to resolve it.

If you receive the following synchronization error is in the synchronization log file:

Error Customer SubmitCustomerBatch: error while creating customer Mike Smith {640437EF-BB94-42AC-A59F-92EA45881892}: The name “Mike Smith” of the list element is already in use.

This message is received when attempting to sync a customer to QuickBooks where the name already exists elsewhere. This can occur if a customer shares the same name as a customer or a vendor. 

You can resolve this sync error by following the steps below:

1. Locate the duplicate name in QuickBooks in the following lists:
   1. Customer Center
   2. Vendor Center
   3. Employee Center
   4. Other Name List
   5. Item Name List (consider filtering to view inactive items)
   6. Chart of Accounts
2. Rename the duplicate name in QuickBooks. You could add '-1', '(QB)', or '(DUP)' to the end of the name in Quickbooks, for example.
3. If Mike Smith already exists as a vendor, change the existing vendor to Mike Smith (Vendor). This will not affect the name that prints on checks.
4. Run a Synchronization. Once another sync is done, the sync error should be gone.
5. If needed, merge duplicate names created from the sync following the steps listed in the linked article. 
6. Run another sync.

QuickBooks treats “Mike Smith” and “Smith, Mike” as duplicates. QuickBooks prevents having the same name used in other lists. Please be sure there are no variations of the same name.