POS is not warning when unrecognized UPC is scanned. How do I fix?

I'll show you how to fix that, SandyOV

You can turn on the Bring back all one time messages option in the settings to reactivate all the warning message. Here's how:

1. Go to the File menu.
2. Select Preferences, then choose Company.
3. Click the General tab.
4. Tick the Bring back all one time messages checkbox.
5. Click OK to apply the changes.

Additionally, I recommend reading this article to learn more about the scanner the interprets barcodes/UPCs in QuickBooks Point of Sale: Point of Sale barcodes and UPCs defined.

Just add a comment below if you have any other concerns. The Community always has your back.

We tried this and it will work on a po but not the receiving voucher and the headquarters store it will work but not on the remote locations?

Thanks for joining in, @Amyshr1120. 

I want to help ensure your scanner will work with QuickBooks. Please know that you meet the specification or format that is needed:

• The scanner must support EAN-13 (International Article Number, formerly European Article Number) and Code-128 barcodes
• The scanner must produce a single carriage return at the end of the barcode.

The Barcode Scanner Tester App will help check that QuickBooks will recognize your scanner.

check out these handy articles below about barcode scanning in QuickBooks:

• Set up and use barcode scanning in QuickBooks Desktop.
• Barcode scanning in QuickBooks.
• Set up and use Warehouse Manager App.

Get back to us if you have additional concerns. We are always willing to assist.