How do I detect and process duplicate customers?

Some environments do not (or no longer) actively check for duplicate customer e-mail addresses. The dashboard block Duplicate customers signals these and offers a guided wizard to clean them up in one go.

When does the block appear

The block is an optional block for the general admin dashboard: an administrator adds it, see how to add a block to a dashboard. After that it is only shown when all conditions are met:

• At least one of the settings Require unique email or Find customer by email is on. If both are off, the block stays hidden – duplicates are then not considered an anomaly.
• There are actually customers sharing the same (case-insensitive) e-mail address.
• Only customers without a company link count. Multiple contacts with the same address under one company is usually a deliberate choice and is therefore not signalled.

What the block shows

One row per e-mail address with duplicates: the address, the customer that will remain after merging (the oldest customer), the number of customers with this address, and the Merge button. That button is only visible with the right action_customer_merge. The block shows at most 10 addresses (most duplicates first); if there are more, a footer line reports how many addresses are not shown. The block refreshes automatically after every merge.

The merge wizard

The Merge button opens a guided comparison per e-mail address:

• At the top: the e-mail address, the number of duplicates found and the position (e.g. “Duplicate 1 of 9”).
• On the left is the customer that remains, on the right the current duplicate. The arrow buttons browse back and forth through all duplicates.
• Per field you tick which value is kept – identical to the regular Merge customers function. Below that is a comparison of linked data (bookings, contacts, invoices, orders, subscriptions, gift vouchers and punch cards).
• The Merge now button merges the shown duplicate into the customer that remains, and then immediately shows the next duplicate. Once every duplicate for that address is processed, the wizard closes itself.

What exactly gets carried over in a merge (and what is permanently lost) is described at Merge customers.