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Common error messages

This section is about the errors that might occur when you run the Data Migration Tool, and how to deal with them.

Source documents/fields not mapped

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

In rare cases, the message might mention Destination documents or Destination fields instead of source ones.


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

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

Possible solutions

  • Install the corresponding Magento 2 extensions from Magento Marketplace

    If the conflicting data originates from an extension which adds own database structure elements, then the Magento 2 version of the same extension may add such elements to the destination (Magento 2) database, thus fixing the issue.

  • 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:


Before ignoring entities, make sure you do not need the affected data in your Magento 2 store.

Class does not exist but mentioned

Class <extension/class_name> does not exist but mentioned in:
<eav_attribute.frontend_model> for <attribute_id=196>


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

Possible solutions

  • Install the corresponding Magento 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.
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

Mismatch of entities in the document: <DOCUMENT>


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

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


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