Handle with Care: Avoiding Catalogue Chaos When Bulk Importing Products into Shopify

If you have been around product creation as long as I have, you know the feeling. Creating, formatting, uploading, and fixing listings for hundreds or thousands of products can take days of work. Using Shopify’s CSV import should, in theory, make that process faster. But if you do not handle it correctly, it can quickly turn into a clean-up nightmare that lasts for weeks.

This blog explains why the “Overwrite products with matching handles” option in Shopify can easily create problems, what happens when you skip it, and how both choices can cause data loss, duplicates, and messy catalogs if you are not fully aware of your existing handles. I am also adding insights from my own years of product creation experience, since I have seen almost every kind of catalog disaster imaginable.

The Setting

When you import products into Shopify using a CSV, you get two main options. You can check “Overwrite products with matching handles.” This means if your CSV includes a handle that already exists in your store, Shopify will overwrite the product with the data from your CSV. Or you can leave it unchecked, which means Shopify will only add new products and ignore the ones that already exist.

It sounds simple. But it only works if you already know every handle in your catalog. And in reality, most people don’t. Many stores have been managed by multiple people, contain products from old imports, or were migrated from another platform. That means you often have no clear picture of which handles already exist, which products are active, or whether the handle in your CSV actually matches the right listing.

The Two Big Risks

1. Risk of Overwriting the Wrong Product

If you use the overwrite option without matching handles correctly, you might overwrite the wrong product or delete valuable data. For example: You assume a product called “Blue Widget” has the handle “blue-widget,” but the live store version uses “widget-blue.” When you import your CSV with overwrite enabled, you might replace an entirely different product or lose data on the one you meant to update. Blank fields are also dangerous. When you overwrite a product, any field that is empty in your CSV will replace the existing data with a blank value. That means you can easily delete descriptions, images, or tags without realizing it.

2. Risk of Creating Duplicate or Missing Products

If you leave the overwrite option unchecked, you avoid accidental overwrites, but you still risk duplicates. If your CSV has a product handle that already exists but you forgot to enable overwrite, Shopify will treat it as a new product and create a duplicate version. On the other hand, if you intended to update an existing listing but used the wrong handle, Shopify will think it is new and create another copy instead of updating the original. This leads to two versions of the same item, collections filled with duplicates, and a huge manual clean-up effort later.

Why This Happens So Often

Based on my own product creation work, these are the most common causes:

• Large catalogs where no one maintains a clean master handle list
• Stores managed by multiple people, each using different naming systems
• CSV files created outside of Shopify, using old or mismatched handles
• Imports that combine new and existing products without separating them
• Lack of testing before a full import
• Complex collections and metafields that become inconsistent when duplicates appear

When that happens, a project that could have been completed in a few days turns into a weeks-long recovery process. It often means checking each product one by one, deleting duplicates, correcting collections, re-adding missing data, and restoring product details that were accidentally erased.

Best Practices: How to Protect Yourself

1. Export Your Existing Products First

Always start by exporting your current catalog. This gives you an accurate list of handles, SKUs, and titles that already exist. It becomes your reference file.

2. Compare Handles Before Importing

Open your new CSV and compare the handle column to your exported list. Make sure every product you plan to update has a handle that matches exactly. Even one small difference can break the match.

3. Separate “Update” and “New” CSV Files

Never mix old and new products in the same import. Create one CSV for products you are updating and another for products you are adding for the first time. This prevents confusion and reduces the chance of duplicate handles.

4. For Updates, Use Only the Fields You Need to Change

If you are updating existing products, make a CSV with only the handle, title, and the fields you want to modify. Leave everything else out so you do not accidentally wipe data.

5. For New Products, Ensure Handles Are Unique

Before adding new listings, check that none of your new handles already exist in the store. If they do, rename them before uploading.

6. Test on a Small Sample

Do not upload your entire catalog at once. Test with 5 to 10 products first. Check that updates work correctly, no duplicates appear, and no data disappears.

7. Backup Before Every Import

Export your entire catalog before you do anything. If something goes wrong, you can use that file to restore your data or rebuild listings more easily.

8. Audit After Every Import

When the import is done, search for duplicates, verify that prices, descriptions, and variants look correct, and confirm that your changes actually applied to the right products.

9. Fix Mistakes Quickly

If you notice duplicates or incorrect overwrites, act fast. Identify which products are wrong, delete duplicates, and reimport corrected versions before more edits are made.

Final Thoughts

Bulk importing products into Shopify with CSV can be an amazing time saver, but only when done with precision. The “Overwrite products with matching handles” option is powerful but risky. Without full awareness of your existing handles, you can easily end up with wrong products, blank data, or dozens of duplicates.

The key is preparation. Always back up, separate your CSVs, test before a full run, and double check every handle. Spending a few extra hours in preparation can save you from weeks of clean-up later.

After years of working on catalog creation across many platforms, I can say one thing for sure: clean data and handle accuracy are what separate a smooth import from a disaster. Handle your handles carefully, and your catalog will thank you.