Snowflake connector: "We cannot convert the value null to type Text"

## Summary

Power BI Desktop fails to connect to Snowflake after the recent automatic upgrade of the system SNOWFLAKE application database in our account. The built-in Snowflake connector throws **"We cannot convert the value null to type Text"** during the database enumeration step, before any database is selected — so no database in the account is reachable from Power BI.

This started on 2026-06-12, coinciding with the SNOWFLAKE application upgrade to v94500.

## Environment

• - **Power BI Desktop**: 2.155.756.0 64-bit (June 2026), latest build
  - **Connector**: Built-in Snowflake connector (not custom)
  - **Snowflake account**: AZURE_WESTEUROPE region
  - **SNOWFLAKE application version**: 94500 (upgraded 2026-06-12)

## Exact error

​```
We cannot convert the value null to type Text.
​```

The error is raised by `Snowflake.Databases(...)` while building the database list — i.e. before the user picks a database/table.

## Root cause (confirmed with Snowflake Support)

`SHOW DATABASES` in our account now returns the SNOWFLAKE application database with **empty/null `owner` and `owner_role_type`** columns:

| field | BI_DB (works) | SNOWFLAKE (breaks PBI) |
| ----------------- | ------------- | ---------------------- |
| kind | STANDARD | APPLICATION |
| owner | <a_role_name> | '' (empty/null) |
| owner_role_type | ROLE | '' (empty/null) |

APPLICATION-type databases do not have the standard ownership model, so these fields are empty by design on Snowflake's side. The Power BI Snowflake connector reads them as **non-nullable Text**, fails on the null, and aborts the **entire** database list — making every database in the account unreachable, not just SNOWFLAKE.

Snowflake confirmed this in support and acknowledged it is a connector-side bug: their stance is that the application DB's owner fields are intentionally empty, and the connector should handle nulls gracefully.

## What I already tried

• - **Read-only role scoped to BI_DB only.** The SNOWFLAKE database is still visible to it via default grants to `PUBLIC` on the application role `SNOWFLAKE.PUBLIC` and on `SNOWFLAKE.*` database roles (`CORE_VIEWER`, `CORTEX_USER`, etc.).
• 
  - **`REVOKE USAGE ON DATABASE SNOWFLAKE FROM PUBLIC` as ACCOUNTADMIN** → fails with `Insufficient privileges`. These grants are system-managed and not revocable. So hiding the SNOWFLAKE DB from a BI role is not possible.
• 
  - **Direct SQL query via the standard connector** — does not help, because the standard connector still calls `Snowflake.Databases(...)` during authentication, before the database is chosen.
• 
  - **ODBC/DSN via the Snowflake ODBC driver** — works as a fallback because it bypasses Power Query's database enumeration, but requires re-tooling every existing report.

## Ask

• Could the Power BI Snowflake connector be updated to **tolerate null / empty `owner` and `owner_role_type` text values** in the output of `SHOW DATABASES`, so that the presence of an APPLICATION-type database (notably the system SNOWFLAKE DB present in every account) does not break the entire connector?
  
  
• If anyone from the Power Query / Snowflake connector team is around, this is currently blocking all Power BI work in our tenant. Happy to provide more diagnostics (Mashup trace, full `SHOW DATABASES` output, etc.) on request.
  
  
• If you are hitting the same error after a recent Snowflake account upgrade — please reply on this thread so we can collect impact for Microsoft.