Symptoms
The ShareGate migration tool displays the following error:
The list content type X could not be copied because its parent type is missing and the closest parent site content type Y is already used by the list content type Z.
Details
For every list content type, there is a parent content type at the site level (a site content type). A SharePoint list cannot contain multiple list content types that point to the same parent site content type.
During a migration, the ShareGate migration tool will attempt to preserve the hierarchy of your source content types at the destination. If you are migrating a list with list content types that have a parent site content type missing from the destination, the app will attempt to use the next closest parent. The app is unable to do so if this creates multiple list content types with the same site content type.
To avoid this error, you can:
- Restore any missing parent content types at your source before your migration.
- Manually create the necessary site content types at the destination before your migration.
- Manually map the list content types to a specific parent content type at the destination during your migration.
- Create the list at the destination using the source list template to preserve the actual content types hierarchy.