Power Query Problems

Handle Excel Power Query Data Source Connection Errors During Scheduled Refresh

Tauseeq Magsi Oct 15, 2026 869 views

Question details

The user needs a way to handle occasional connection errors during scheduled Power Query refreshes, as unhandled connection failures generate a dialog box that stops further periodic refreshes until manually closed.

Handle Excel Power Query Data Source Connection Errors During Scheduled Refresh

Product: Microsoft Excel
Device & OS: not provided
Scenario: Running periodic scheduled data refreshes connecting to a remote OLE DB server via an IP address.
Observed behavior: When the remote server cannot be reached, a 'Data source could not be reached' error dialog pops up, blocking subsequent scheduled refreshes until it is manually closed.

Before you start

Ensure you have access to the Power Query Advanced Editor and verify your network stability and OLE DB provider settings before modifying the query code.

Solution 1Recommended

Implement Power Query M Language Error Handling

Catch connection errors using the try...otherwise statement in the Advanced Editor to return a fallback value (like an empty table) instead of triggering a blocking error dialog.

By default, Excel interrupts automated background refreshes with a dialog box when it fails to connect to a data source. To bypass this manual interruption, you can modify the M code to gracefully handle the failure.

Open Power Query Editor

In Excel, go to the 'Data' tab on the ribbon and click 'Get Data' > 'Launch Power Query Editor'.

Access the Advanced Editor

In the Queries pane on the left, right-click the query that is failing and select 'Advanced Editor'.

Apply Try...Otherwise Syntax

Locate the source connection step (e.g., your OLE DB connection string). Wrap the connection step to return an empty table upon failure. For example: Source = try OleDb.DataSource("...") otherwise #table({},{}).

Save and Load

Click 'Done' to close the Advanced Editor, then click 'Close & Load' on the Home tab to apply the new error-handling logic.

Implement Power Query M Language Error Handling

Automated Handling Achieved: Returning an empty table allows the query to finish executing without displaying a blocking dialog, enabling the next scheduled refresh to run seamlessly.

Solution 2

Configure Explicit Timeout Settings

Prevent prolonged connection attempts by explicitly defining a timeout duration in your connection parameters.

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Frequently Asked Questions

Why does my Excel scheduled refresh stop when an error occurs?

By default, Excel requires manual intervention to close error dialogs (like 'Data source could not be reached') to ensure users are aware of connection failures. This blocks background processing until the prompt is dismissed.

Can I clear the Power Query error dialog automatically?

You cannot programmatically close the Windows dialog box itself once triggered. Instead, you must prevent the dialog from appearing by catching the connection error within the Power Query Advanced Editor using the 'try ... otherwise' syntax.

Where do I place the error handler in my M code?

Place the 'try ... otherwise' statement exactly at the step where the connection is established. For example, wrap your 'Source' variable assignment to catch OLE DB or Web connection failures immediately.

What happens if I return an empty table during a refresh failure?

Returning an empty table clears the old data and loads a blank dataset for that specific refresh period. Crucially, it prevents the error dialog from blocking the application, allowing the next scheduled refresh to execute normally and fetch data once the server is online.

Excel & Data Problems