Can You Undo a Customer Merge in Shopify?

You can't undo a customer merge in Shopify. Shopify's help documentation says that after the profiles are merged, you can't reverse the process, and there's no unmerge button in the admin, the mobile app or the API. If you merged two different people, the fix is a manual rebuild: create a fresh profile for the second person, move their orders onto it, and clean the leftovers off the profile that was kept.

That rebuild is possible, but it's slower than the merge was, and some details can't be recovered from Shopify alone. This guide covers what a merge destroys, how to separate a wrong merge step by step, and how to set things up so a bad merge costs you minutes instead of an afternoon.

Can you undo a customer merge in Shopify?

No. The only point where you can back out is before you confirm. Once you click Merge and then Confirm, the change is permanent.

Shopify's merge flow gives you two chances to stop. In Customers > [customer] > More actions > Merge customer, the Merged customer section shows what will be kept and discarded, and View merge details lists it in full. Shopify's help page says that if information on the two profiles conflicts, you can cancel the merge, adjust each profile separately, and then merge again. After confirmation, none of that is available.

The API is no different. Shopify's GraphQL Admin API documents a customerMerge mutation, which runs the merge as an asynchronous job, and a customerMergePreview query that shows the result in advance. It documents nothing that splits a merged profile. The resultingCustomerId the API returns is the one customer ID that lives on, and Shopify's docs say to treat it as authoritative.

Shopify also doesn't notify the customer about a merge, so a wrong merge can sit unnoticed until a customer signs in and sees someone else's orders, or support spots a strange address.

What is lost when two customers are merged?

Single values from the discarded profile are gone, and combined lists lose track of where each item came from. Orders survive intact, which is what makes a repair possible at all.

Here is what a merge does to each part of the profile, and how much of it you can get back. The merge behavior comes from Shopify's help page; the recovery column is what's realistic without a backup.

Two rows matter most. The customer ID can't come back, which affects any app that stored it (loyalty, reviews, helpdesk). And marketing consent is the field you should be most careful with: after a merge, a person who never subscribed may now show as subscribed. Don't copy that status onto the new profile unless you can show the customer actually agreed.

For the full picture of how each field behaves during a merge, see what happens when you merge customer accounts in Shopify.

How do you separate customers that were merged by mistake?

Rebuild the second person's profile and move their orders to it. The orders are the anchor: each one kept its own contact email, shipping address and line items, so you can tell whose they are even after the merge.

1. Make a list first. Open the merged profile and write down which orders, addresses, tags and note lines belong to the second person. Use each order's contact email and shipping address to sort them.
2. Check that the email is free. The merge discarded one email, so it's no longer on any profile. Search for it under Customers to confirm. Shopify requires emails to be unique across customers, so if something already uses it, sort that out first.
3. Create the new profile. Go to Customers > Add customer and enter the second person's name, email, phone and address.
4. Move the orders. See the next section for the two ways to do this.
5. Clean up the kept profile. Delete the second person's addresses, remove their tags, cut their lines out of the note, and correct the phone and name if the wrong ones were kept.
6. Handle consent deliberately. Set marketing consent on both profiles only from records you trust, such as a backup or the customer's own word.
7. Tell both customers. Each needs to know which email to sign in with, since the merge may have left one of them signing in to the wrong account.

Do this soon after you notice. Every new order, tag or note added to the merged profile is one more thing to sort.

How do you move orders back to the right customer?

In the admin you can unlink an order; to attach it to a different profile, use the API. That split is the main practical limit of a repair.

Shopify's help page on editing customer details on orders documents Remove customer: open the order, click the menu in the Customer section, click Remove customer, and confirm. This unlinks the order from the profile without deleting the customer. The same help page doesn't describe adding a different customer to an existing order, and Shopify's merge documentation still says orders are permanently associated with the account that placed them and can't be moved by editing the order's contact email.

The API goes further. Shopify's developer changelog of May 23, 2025 announced two GraphQL Admin API mutations in version 2025-07: orderCustomerRemove and orderCustomerSet. Shopify described orderCustomerSet as new functionality not previously possible in GraphQL or REST. It takes an order ID and a customer ID, needs the write_orders scope (or write_quick_sale), and the user must have permission to manage the order.

A worked example: say a store merged "J. Smith" with a work email (3 orders) into "J. Smith" with a personal email (9 orders), but they were two different people. The kept profile now shows 12 orders. The fix is one new profile for the work-email Smith, three orderCustomerSet calls (one per order ID), and removing that person's office address and any tags that came with it. If you aren't comfortable with the API, a developer or an order-editing app can make those calls; unlinking with Remove customer in the admin is the fallback.

How do you make a merge safe to get wrong?

Back up first, merge only pairs you're sure of, and work in small batches. Since Shopify won't undo a merge, your own records are the undo.

• Export before you merge. Go to Customers > Export and choose All customers (or Selected customer). Tick Customer tags and Customer metafields under Fields included. Exports over 50 customers are emailed to you. Shopify's help page doesn't list a customer ID column in that CSV, so the email is your key to match records later.
• Keep the order list too. An export from Orders keeps a record of which email placed which order, which is exactly what you need to sort orders during a rebuild.
• Only merge clear matches. The same email after normalizing, the same phone, or the same name and address is strong evidence. A shared first initial and surname is not. How to find duplicate customers in Shopify covers how to rank matches by confidence.
• Read the preview. In Merged customer, check the email, phone, name and default address before confirming. Click Change contact information if the wrong ones are selected.
• Batch small and log it. Merge a manageable set, note which pairs you merged, and spot-check a few kept profiles before you continue.
• Look out for refusals. Some pairs won't merge at all, which is a different problem from a wrong merge. Why Shopify won't merge some customers lists every blocker.

What about apps that stored the old customer?

Check each app that keeps its own copy of your customers. Email, loyalty, reviews, subscriptions and helpdesk tools often key records to an email or a Shopify customer ID, and a merge followed by a rebuild changes both.

Shopify's documentation can't tell you how a third-party app reacts, so look at each app's own docs. Loyalty points and other balances need the most attention, because a balance attached to the kept profile may now include points that belong to the second person. Move those inside the app, and do it before the customer notices.

How Twinfold helps

Twinfold is a Shopify app by NewClick (independent, not made by Shopify) that finds duplicate customers and merges them in bulk through Shopify's own customer merge. It can't undo a merge either, because Shopify doesn't allow it. What it does is make a wrong merge less likely and easier to trace.

Each group shows Why they match (email variant, same phone, or same name and address) and a High, Medium or Low confidence. Low-confidence groups and groups of more than 10 profiles go to Review manually and are never included in the one-click bulk preview, and Not duplicates dismisses a group for future scans. Every merge is previewed with Shopify first, and you tick I understand that merged customers can't be unmerged before clicking Merge N customers. Afterward, Merge history and Download CSV give you a log of what was merged, which is the list you'd start from if a pair ever needs to be rebuilt.

A merge takes seconds and a repair takes much longer. Spend the extra minute on the preview.