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Receiving a "Duplicate Document Number Error" in Quickbooks?

Let's fix the error and get your invoices back on track.

Mark Epchteine avatar
Written by Mark Epchteine
Updated over a year ago

If you're reading this, chances are you received the following error:

"Duplicate Document Number Error: You must specify a different number. This number has already been used."

This means the invoice number that is trying to be processed already exists in Quickbooks. We'll want to change a few settings to get around this.

The Fix

  1. In Quickbooks, head over to Settings followed by Account and Settings >> Sales.

  2. Ensure Custom Transaction Numbers is OFF.

    QBO Custom Transaction Numbers.png

3. Now click on the Advanced tab on the left.

4. Under "Other Preferences" ensure "Warn if duplicate check/bill number is used" is also set to OFF.

QBO Warn if duplication cheque number.png

Now you'll be good to go - no more error!

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