Very good question....
I can go through the reasons for this, or the solutions, or both??
Why is it so?
You are receiving this error MESSAGE because you have the QuickBooks Sales and Customers Company PREFERENCE "Warn about duplicate tax invoice numbers" turned ON.
The Easy Solution to the Symptom:
If you don't want to get this error when posting your EOD file, simply turn it off and it's fixed. However, this merely fixes the symptom (the error message), not the cause.
Root Cause:
Your POS file is getting out of sync with your QB file, and this often happens if customer invoices (not receipts, but actual customer account invoices) are generated on both POS & QuickBooks during the day. **I personally don't encourage this and advise my clients to use one or the other (if at all possible).
Some rough pointers (questions to ask yourself) to overcoming this issue:
Look at the syntax structure of your invoices. ie. Are they 000001 to infinity, or do they re-set every day, are they prefixed with INV etc... How can you best incorporate the POS set up options (re-set receipt numbers daily for example) with the QuickBooks options so they don't overlap.
Can you provide the customer a Delivery Docket at POS (using the print invoice option) and mail/email the Tax Invoice?
Can a Premier user license be used at POS so that account invoices are generated using QuickBooks?
Is the sale sent to the "back-office" (via secondary printer) at POS where the invoice is immediately genertaed by a designated staff member?
Do you look at a 3rd party application?
What reports can be customised in QuickBooks to ascertain the latest Inv number at the time of processing an additional invoice?
How can you remotely access the POS terminal(s) to view transaction data?
Can you send duplicate invoices to the back office so all staff know the next number in sequence?
I have used various suggestions above (plus others) at my POS clients to achieve various outcomes. Variables such as business type, traffic, number of POS terminals, network set-up etc... etc.. all add to the mix.
Hopefully some of these suggestions will point you in the right direction. Of course, you could just turn off the Preference option as I first suggested, although I never do this as it can lead to multiple invoice numbers and mass confusion. It all comes down to planning the best procedures for your business.
Regards,
Jason Hollis
Accredited QuickBooks Partner
www.quickbooksolutions.com.au