Forum Discussion

adf_user's avatar
adf_user
Copper Contributor
Apr 29, 2026

Copy data using ODBC fails: "Format of the initialization string [...] starting at index 0"

We ran into a frustrating issue in ADF where a Copy activity using an ODBC source (Databricks) consistently failed with the same error, despite the connection test and data preview working perfectly ...
Jamony's avatar
Jamony
MCT
Jul 15, 2026

This error is being thrown by System.Data before Databricks sees the table or query, so I would focus on the linked-service payload rather than mappings.

 

ADF's ODBC connector documents connectionString as excluding credentials. Keep Driver, Host, HTTPPath, AuthMech, Auth_Flow, Auth_Client_ID, Auth_Scope and OIDCDiscoveryEndpoint there, but move Auth_Client_Secret=<secret>; into the linked service's credential SecureString (ideally a Key Vault reference) and use Anonymous authentication. That also avoids Terraform/braces producing an invalid connection string when the activity resolves the secret.

 

For Entra service-principal M2M, also confirm the SHIR has Databricks ODBC driver 2.8.2 or later and use the documented scope 2ff814a6-3304-4ab8-85cb-cd0e6f879c1d/.default.

 

Then publish and run a minimal one-row Copy on the same SHIR. If it still fails, upload the activity's SHIR logs from Monitor and check Applications and Services Logs > Integration Runtime; the report ID should expose the resolved runtime failure.