If individual products are disapproved rather than the whole account, it is almost always one of a handful of catalog fields: the image, the barcode, the brand, the title or the description. Each one has a published rule, and Shopify calls some of them by a different name than Google does, which is why they end up empty.
The confusing part is that Merchant Center tells you the policy that was broken, not what to change in your store. And the field names rarely match: what Google calls "brand" is called "Vendor" in Shopify, and what it calls "GTIN" is the "Barcode" field, buried in the Inventory section.
It is also worth separating two very different situations. If individual products are disapproved, it is a catalog problem and this page covers it. If the whole account is suspended, that is usually not about your products at all — it is about what your store publishes, and that has its own page.
Below is each rule with Google’s own words. We check all of them, and quoting the policy is the point: you should not have to take our word for it.
We only read what your store already publishes to any visitor. No access, no passwords, nothing about your customers.
«Use a URL that points to an image in a supported file format.»
This product has no image at all. Without one, Google will not show it. Upload at least one photo of the full product, with no collages and no text overlaid.
«Meet these size requirements: At least 500 x 500 pixels»
The main image is smaller than the 500 x 500 pixel minimum Google requires. Upload a larger one: Google recommends around 1500 x 1500 so it looks right in every format.
«Products with missing or incorrect GTIN [gtin] attributes may have limited visibility.»
Add the manufacturer's barcode (GTIN) to this product. If the product genuinely has none assigned — handmade or made-to-order items, for example — you can leave it empty and Google accepts that. Never make a number up: Google says explicitly not to guess it.
«Required for each product with a clearly associated brand or manufacturer.»
This product has no brand (in Shopify that is the "Vendor" field). Google requires it for any product with an associated brand, including when you are the manufacturer, as with handmade or custom items. If it truly has no brand — a book or a poster, say — you can leave it empty.
«Don't use capital letters for emphasis. Capitalized text is common in spam and untrustworthy ads.»
This title uses capital letters for emphasis. Write it in normal sentence or title case. Google does allow caps for acronyms, phone numbers, countries and currencies: the problem is shouting, not abbreviations.
«Also avoid gimmicky ways of drawing attention such as all caps, symbols, HTML tags, and promotional text.»
This title contains promotional text (for example "free shipping", "sale" or a discount percentage). The title describes the product; promotions belong in other fields. Remove it and leave only what the product is: type, brand, model and key attributes.
«Not following these guidelines can lead to disapprovals or limit the serving of your ads.»
This product has no description, or it is too short to describe anything. Google requires one for every product and uses it to understand what you are selling. Write at least a couple of sentences about the product itself, with no shipping details, promotions or references to other products.