Thanks for joining the conversation, @Robp475.

I can see the importance of having the feature to prevent sales when there's zero or negative stock in inventory items. Currently, that option is unavailable in QuickBooks Point of Sale (POS).

For now, we can share this valuable insight with our Product Development team by going to the Help menu. You'll find a Send Feedback link that lets you submit your comments and product suggestions, or report a program bug. This way, they might consider adding this option to our product updates in the future. 

You can also visit the Customer Feedback page to track the status of your suggestions.

In addition, you might encounter issues with matching amounts in your inventory report for both QuickBooks Desktop and Point of Sale. You can refer to this article for possible reasons: Inventory valuation amounts in Point of Sale and QuickBooks Desktop do not match.

Please don't hesitate to come back to this thread if you have additional clarifications about inventory items. We're always around to help. Have a great day!