I see quite a few others have had similar issues with the following error:

This manufacturer barcode is linked to more than one ASIN. Please check if you entered the correct product ID (ISBN, UPC, or EAN).

I also see that not many of these posts show an actual resolution. We run into this issue frequently, and have no idea how to proceed without new headaches down the road.

We are a third-party seller. We do not manufacture or own the brands. We do not create UPCs or ASINs. We cannot create listings. We scan the barcode of our inventory, and find the correct product listing on Amazon. We create a Merchant SKU that ties our inventory to the specific ASIN. Ideally, we choose to send the product using the existing manufacturer's barcode/UPC. Amazon will determine whether or not we will be required to affix an Amazon label to the product.

When we get this error, we can check to see that we entered the correct product ID until we are blue in the face. This does not solve the problem, likely because the error is not properly explained. It should read "This ASIN is linked to more than one manufacturer barcode." For example, we just had this error on a product that only nets one result if scanned by manufacturer barcode/UPC. There is only one ASIN for this product. When we review the listing, Product Details/Technical Information reflects two GTINs (including the UPC on our product) and three UPCs (including the UPC on our product). The manufacturer certainly has the right to change the UPC while maintaining the Brand/Model Number/Specs for their products. We can assume that this may be the best explanation as to why we are required to use an Amazon Barcode label instead of the manufacturer's existing UPC. We have no qualms with printing and affixing the Amazon barcode over the UPC, which should be enough to solve the problem.

That being said, we do not know what else can be done to resolve this issue and proceed to adding the inventory to a shipping plan.

Before "Send to Amazon," there was a similar error called a "Barcode/ASIN Conflict." The best way for us to resolve that error was to create a new Merchant SKU for the same ASIN, usually resulting in the required Amazon barcode label. However, this seems to be a slippery slope. If we already have active inventory at Amazon Fulfillment Centers under the previous Merchant SKU tied to the same ASIN, it may result in the dreaded "Stranded Inventory."

We are seeking a definitive pathway to fix the error "This manufacturer barcode is linked to more than one ASIN."