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Error 6140 occurs in QuickBooks Online (QBO) when you attempt to save a transaction using a document number that has already been assigned to another entry in your account. This duplicate could involve a check number, bill number, or journal number.
To resolve the issue, review the transactions that triggered the error, identify the entry with the duplicate number, and update it with a unique number to prevent conflicts. Ensuring each document number is unique helps maintain organization and data accuracy in QBO.
Feel free to reply to this thread if you need further assistance with any QuickBooks concerns.
