Data Migration Tool troubleshooting

Last update: 2023-07-27
  • Created for:
  • Developer

This article provides solutions for errors that might occur when you run the Data Migration Tool.

Source documents/fields not mapped

Error messages

  • bash Source documents are not mapped: <EXTENSION_TABLE>
  • bash Source fields are not mapped. Document: <EXTENSION_TABLE>. Fields: <EXTENSION_FIELD>

In rare cases, the message might mention

Destination documents


Destination fields

instead of source ones.


Some Adobe Commerce version 1 entities (in most cases, coming from extensions) do not exist in the Adobe Commerce version 2 database.

This message appears because the Data Migration Tool runs internal tests to verify that tables and fields are consistent between source (Adobe Commerce 1) and destination (Adobe Commerce 2) databases.

Possible solutions

  • Install the corresponding Adobe Commerce 2 extensions from Commerce Marketplace. If the conflicting data originates from an extension which adds own database structure elements, then the Adobe Commerce 2 version of the same extension may add such elements to the destination (Adobe Commerce 2) database, thus fixing the issue.
  • Use the -a argument when executing the tool to auto resolve errors and prevent migration from stopping.
  • Configure the Tool to ignore the problematic data.

To ignore database entities, add the <ignore> tag to an entity in the map.xml file, like this:

            <!-- Ignore `sales_flat_invoice_grid` table -->
            <!-- Ignore `address_id` field of `sales_flat_order_address` table -->

Before ignoring entities by map file or using the -a option, make sure you do not need the affected data in your Adobe Commerce 2 store.

Class is not mapped in record

Error message

Class <extension/class_name> is not mapped in record <attribute_id=196>


A class from Adobe Commerce 1 codebase could not be found in Adobe Commerce 2 codebase during the EAV migration step in our developer documentation. In most cases, the missing class belongs to an extension.

Possible solutions

  • Install the corresponding Adobe Commerce 2 extension.
  • Ignore the attribute that causes the issue. For this, add the attribute to the ignore group in the eav-attribute-groups.xml.dist file.
  • Add class mapping using the class-map.xml.dist file.

Foreign key constraint fails

Error message text

Foreign key <KEY_NAME> constraint fails on source database. Orphan records id: <id_1>, <id_2> from <child_table>.<field_id> has no referenced records in <parent_table>


There are missing database records in the parent_table to which the field_id of the child_table is pointing to.

Possible solution

Delete the records from the child_table , if you do not need them.

To keep the records, disable the Data Integrity Step by modifying the Data Migration Tool’s config.xml .

Duplicates in URL rewrites

There are duplicates in URL rewrites:
Request path: towel.html Store ID: 2 Target path: catalog/product/view/id/10
Request path: towel.html Store ID: 2 Target path: catalog/product/view/id/12


The Target path in a URL rewrite must be specified by a unique pair of Request path + Store ID . This error reports two entries that use the same Request path + Store ID pair with two different Target path values.

Possible solution

Enable the auto_resolve_urlrewrite_duplicates option in your config.xml file.

This configuration adds a hash-string to the conflicting records of URL rewrites, and shows the resolution result in your command line interface.

Mismatch of entities

Error message

Mismatch of entities in the document: <DOCUMENT> Source: <COUNT_ITEMS_IN_SOURCE_TABLE> Destination: <COUNT_ITEMS_IN_DESTINATION_TABLE>


The error occurs during the Volume Check step. It means the Adobe Commerce 2 database record count of the document is not the same as in Adobe Commerce 1.

Missing records happen when a customer places an order during migration.

Possible solution

Run the Data Migration Tool in Delta mode to transfer incremental changes.

Deltalog is not installed

Error message

Deltalog for <TABLE_NAME> is not installed


This error occurs during incremental migration (in our developer documentation) of changes to data. It means deltalog tables (with prefix m2_cl_*) were not found in the Adobe Commerce 1 database. The tool installs these tables during data migration (in our developer documentation) as well as database triggers which track changes and fill deltalog tables.

One reason for the error could be that you are trying to migrate from a copy of your live Adobe Commerce 1 store, not from the live store itself. When you make a copy from a live Adobe Commerce 1 store that has never been migrated, the copy does not contain the triggers and additional deltalog tables needed to complete a delta migration, so the migration fails. The Data Migration Tool does NOT make comparisons between the DB of AC1 and AC2 to migrate the differences. Instead, the tool uses the triggers and deltalog tables installed during the first migration in order to perform subsequent delta migrations. In such a case, your copy of the live Adobe Commerce 1 DB will not contain the triggers and deltalog tables that the Data Migration Tool uses to perform a migration.

Possible solution

We recommended testing the migration process from a copy of your Adobe Commerce 1 database to fix your migration issues. After fixing the issues on the copy, start the migration process over again from your live Adobe Commerce 1 database. This will help ensure a smooth migration process.

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