How to See Where Power BI is Pulling Data From

Inherited a Power BI report and have no idea where it's pulling data from? Or maybe you're revisiting a project after months away and can't remember if the data comes from a local Excel file, a shared server, or a web API. It’s a common scenario that can stop any data refresh or update dead in its tracks. This guide will show you several straightforward methods to find exactly where your Power BI data originates so you can troubleshoot, update, and manage your reports with confidence.

Why Does Knowing Your Data Source Even Matter?

Pinpointing your data source isn't just a technical exercise, it's fundamental to maintaining a reliable report. Here’s why it’s so important:

Troubleshooting Refresh Errors: The most common Power BI error, "the data source can't be refreshed," is almost always due to a moved file, expired credentials, or a change in a database schema. Knowing the source is the first step to fixing the problem.
Validating Data Accuracy: If numbers in your report look off, you need to go back to the source to verify the raw data. Is the Excel file updated? Is the SQL query correct? You can't trust your dashboard if you can't trust its foundation.
Updating or Migrating Reports: When a source file's location changes - for instance, moving from a local drive to a shared SharePoint folder - you need to edit the source path in Power BI to keep the connection live.
Understanding Report Logic: To truly understand how a report works, especially one built by someone else, you have to trace the data from its origin through all the transformations in Power Query.

Method 1: The Quick-Look with the Data View

Sometimes you just need a quick hint without diving into the technical backend. The easiest way to get an idea of the data source is by using the visual cues within the main Power BI interface. While this method isn't always comprehensive, it’s a great first place to check.

Here’s how to do it:

Navigate to the Data view by clicking the table icon on the far left-hand pane of Power BI Desktop.
In the Fields pane on the right, you'll see a list of all the tables in your model.
Simply hover your mouse cursor over a table name.

In many cases, a tooltip will pop up displaying information about the table, including its data source. For example, for an imported Excel file, it might show you the file path. For a database connection, it might show the server and database name. It's a simple, fast check that can often give you the answer in seconds.

Method 2: The Definitive Answer in Power Query Editor

For a complete and unambiguous answer, your best destination is the Power Query Editor. This is Power BI's data transformation engine, and it’s where every data source is officially defined and configured. If you want the ground truth, this is where you'll find it.

Getting to the Source Step

Follow these steps to track down your data connection:

From the Home tab in Power BI Desktop, click the Transform data button. This will launch the Power Query Editor in a new window.
On the left side of the Power Query Editor, you’ll see a list of your queries in the Queries pane. Each of these queries corresponds to a table in your report.
Click on the query (table) you want to investigate.
Now, direct your attention to the Applied Steps pane on the right. This lists every single action Power BI has taken to transform the data from its raw state.
The very first step listed is almost always named Source. Click on this step.

Once you click on the Source step, the formula bar at the top of the window will display the underlying M code that defines the connection. This formula is the definitive answer you’re looking for.

Decoding the Source Formula

The M query formula can look intimidating at first, but it's typically easy to read once you know what to look for. Here are a few examples of what you might see for common data sources:

Excel File: You will see an absolute file path.
CSV File: Similarly, it will point to an exact file location.
SQL Server Database: This will show the server name and the database name.
Website or API: This will show a URL.

Checking the Source step in Power Query's Applied Steps is the most reliable way to find your data’s origin, bar none.

Method 3: Manage All Sources in Data Source Settings

What if you want a complete list of every external data source used in your entire Power BI report? This is incredibly useful for getting a birds-eye view or when you need to update credentials or paths for multiple queries at once.

The Data source settings menu is what you're looking for.

On the Home tab of the main Power BI window, click the small dropdown arrow next to the Transform data button.
In the menu that appears, select Data source settings.
A dialog box will open, listing every single unique connection in your .pbix file. You’ll see a list of file paths, server names, and URLs.

This menu is a command center for your data connections. From here, you can:

Change Source: If a file has been moved or a server has been renamed, you can click a source and then use the Change Source... button to point the query to the new location without having to re-import it.
Edit Permissions: If credentials for a database or API have changed, this is where you can update them using the Edit Permissions... button.
Clear Permissions: Forget stale or incorrect credentials for a source.

Method 4: Peeking at the Full Code in the Advanced Editor

Sometimes, complex reports are built using custom functions or tricky transformations that can make spotting the source in the formula bar difficult. For these advanced cases, the Advanced Editor gives you a complete, unobstructed view of the entire M code powering your query.

Open the Power Query Editor (via the "Transform data" button).
Select the query you are investigating from the list on the left.
On the Home tab (within the Power Query Editor), click the Advanced Editor button.

This will open a new window showing the entire script for that query. While it might look complex, the source is almost always defined in one of the first few lines inside the let statement. Look for a line that starts with something like:

The Advanced Editor is your go-to when you need to understand the full data transformation pipeline from start to finish. It’s perfect for debugging complex, multi-step queries someone else built.

Bonus Tip: What if the Data is Coming From... Nowhere?

There's one more possibility: the data wasn't imported from an external file at all. It may have been entered manually directly into Power BI. This is done using the Enter Data feature and is common for small, static tables (like a date reference table or category mapping).

You can identify these tables in the Power Query Editor. When you select the table and look at its Source step, the formula will look like this:

If you see #table(), it's a clear sign that the data isn't being pulled from anywhere else. It exists solely inside your Power BI file. This is crucial to know because it means there's no external file to update - any changes must be made directly within the query itself in Power BI.

Final Thoughts

Figuring out where your data is coming from is a fundamental skill for anyone working seriously with Power BI. Whether you use a quick hover in the Data view or dig into the M code via the Advanced Editor, these methods will equip you to troubleshoot refresh errors, validate information, and keep your reports both accurate and up-to-date.

The steps involved in tracing sources within tools like Power BI - hunting down file paths, checking server credentials, and decoding query languages - are precisely the kind of tedious manual work that slows down teams. At Graphed, we’ve focused on eliminating that friction. We provide dead-simple, one-click integrations with dozens of marketing and sales platforms. You just connect your sources once, and we handle the rest in the background. Instead of managing complex data connections, you can build real-time, interactive dashboards just by describing what you want to see in plain English.