Here are 30 common issues related to Databricks Unity Catalog, categorized by different aspects like setup, security, access control, data governance, integration, and performance.

1️⃣ Unity Catalog Setup Issues

1. Unity Catalog is not available in my Databricks workspace
   • Ensure your workspace is running on a supported Databricks account and region.
2. Cannot enable Unity Catalog for an existing workspace
   • You must migrate workspaces to use AWS IAM roles or Azure managed identities.
3. Error while configuring Metastore
   • Verify that you have the necessary Metastore Admin permissions.
4. Missing catalog or schema in workspace UI
   • Ensure the Unity Catalog Metastore is assigned to your workspace.
5. Cannot upgrade existing Delta Lake tables to Unity Catalog
   • Ensure tables are registered using Managed Tables or External Locations.

2️⃣ Access & Permissions Issues

6. Users cannot see the Unity Catalog Metastore
   • Grant the correct permissions using GRANT USE CATALOG or USE SCHEMA.
7. Error: Permission denied when querying Unity Catalog tables
   • Check if users have SELECT privileges on the table.
8. Admin cannot grant privileges to users
   • Only Metastore Admins can grant high-level permissions.
9. Cannot access external tables registered with Unity Catalog
   • Ensure the storage credential is properly configured.
10. Table exists in Databricks but not visible in Unity Catalog

• Tables must be explicitly registered in Unity Catalog.

3️⃣ External Data & Storage Issues

11. Cannot register external tables in Unity Catalog

• Verify that the external table uses a Unity Catalog-compatible location.

12. Data in Unity Catalog tables is not updating

• Check if the table is using Delta Lake and if the transaction log is up to date.

13. AWS S3 storage location cannot be accessed

• Ensure the IAM role has the correct S3 bucket policies.

14. Cannot use ADLS Gen2 storage for Unity Catalog

• Ensure proper managed identity access and credential passthrough.

15. “Invalid Storage Credentials” error

• The storage credentials must be configured in Unity Catalog with CREATE STORAGE CREDENTIAL.

4️⃣ Delta Sharing & External Access Issues

16. Cannot share Unity Catalog tables using Delta Sharing

• Ensure the recipient has the correct READ privileges.

17. Delta Sharing is not enabled in Unity Catalog

• Contact your Databricks administrator to enable Delta Sharing.

18. External users cannot access shared tables

• Ensure the external organization has a compatible Databricks workspace.

19. Performance issues when querying shared tables

• Optimize the Delta tables using OPTIMIZE and VACUUM commands.

20. Schema changes are not reflected in shared datasets

• Schema evolution needs to be enabled, or re-register the table.

5️⃣ Data Governance & Compliance Issues

21. Cannot track lineage for Unity Catalog tables

• Enable Data Lineage in Databricks settings.

22. Audit logs not capturing Unity Catalog actions

• Ensure Databricks Audit Logs are enabled.

23. Data masking is not applying correctly

• Verify MASKING POLICY is properly assigned.

24. User access logs are missing from the catalog

• Check if Access Logging is enabled in Unity Catalog.

25. Role-based access control (RBAC) is not working

• Ensure the correct groups and roles are assigned in Databricks.

6️⃣ Performance & Query Execution Issues

26. Slow performance when querying Unity Catalog tables

• Use OPTIMIZE ZORDER BY to improve query performance.

27. High latency when using Unity Catalog external tables

• Ensure external storage is optimized with partitioning.

28. Metadata operations on Unity Catalog tables are slow

• Unity Catalog tables have stronger governance rules, which may impact performance.

29. Concurrency issues when multiple users query the same Unity Catalog table

• Increase compute resources or use Databricks Photon.

30. Cannot use Materialized Views with Unity Catalog

• Materialized views require DBR 12+ with Unity Catalog support.

🔍 Conclusion

These are the 30 most common Databricks Unity Catalog issues related to setup, security, data governance, and performance. Let me know if you need solutions or troubleshooting steps for any specific issue!