If you’re going to create a listing whether it’s a variation or a whole parent with multiple variations listed under it, there’s one thing you should always do before you get started.

Always take pictures of the UPC/barcode on the tag, the front and back of the product with the tags visible.

The UPC pictures are important in case you have any trouble creating the listing. You might need to open a case and they’re always going to ask for these pictures as proof that the UPC belongs to the product you say it does.

There will be times when the UPC is already in use, this doesn’t always mean someone stole it. Sometimes it does, but sometimes it’s because brands will reuse UPCs for different seasons. If that makes sense. Old UPCs can be reused for newer products. If that’s the case you might see this error

The SKU data provided is different from what’s already in the Amazon catalog. The standard_product_id data provided matches ASIN B0WHATEVER but the following data is different in the amazon catalog: COLOR. If this is the right ASIN for your product, update your data to match what’s in the Amazon catalog. If it’s not the right ASIN, make sure that your data for standard_product_id is correct.

When this happens first you need to check to make sure you’re using the correct product id. It could be a simple mix up. But once you’ve verified that you’re using the correct UPC and it’s already being used for a different product, you’ll have to open a case, attach the pictures, the template you used to try to create the listings, and the last processing report.

The pictures are photo proof that the UPC belongs to the product you say it does, they can’t help you unless they’re sure you’re using the UPC correctly. Make it easy for them.

The template will show them you’re doing everything correctly. If you don’t attach this when you open the case they’re either going to ask for it or give you generic instructions on how to use a flat file to create a listing. So you might as well beat them to it.

The last processing report will give them the error codes. They’ll either ask for a batch id or this report if you don’t add it. They’re going to need to look at this and use it to examine the template to see what’s wrong.

These cases tend to take a long time to resolve, I recommend getting on the phone once you open the case and talking to someone about it. That’ll clear up any confusion on either end and they’ll be able to start working to resolve the issue faster. In theory all they need to do is basically break the listing. They call it cleaving. They have to separate the UPC from the old listing without deleting it, so you can create the new product listing. It’s a long process so if you’re trying to create a new listing and you run into this problem, you’ll need to decide if it’s worth the time and energy you’ll have to put into interacting with seller central to solve the problem before you can create the new listing.