Tables Appear Under the Unidentified Schema in Microsoft Fabric Lakehouse

Issue

After setting up a Managed Data Lake Service destination with Azure Data Lake Storage (ADLS), some successfully synced tables appear under the Unidentified schema in Microsoft Fabric Lakehouse Explorer instead of the appropriate schema.

Environment

• Destination: Managed Data Lake Service
• Storage: Azure Data Lake Storage (ADLS)
• Platform: Microsoft Fabric Lakehouse

Resolution

To resolve the issue:

1. Wait for the initial sync to complete, then refresh Lakehouse Explorer.
2. Verify that the Delta transaction log is complete and readable.
3. Confirm that each table's folder structure meets the Microsoft Fabric requirements for Delta tables.

Once Microsoft Fabric recognizes the folders as valid Delta tables, the tables appear under the appropriate schema. For more information about connecting your ADLS destination to Microsoft Fabric, see Set up OneLake.

Cause

This issue occurs when Microsoft Fabric detects the table folders in Azure Data Lake Storage but can't validate them as Delta tables. This may happen when the Delta transaction log is incomplete, unavailable, or not yet recognized by Microsoft Fabric.