Power Query Parameters Guide: Dynamic File Paths (Stop Hardcoding!)

The moment you email your Excel report to a colleague, it breaks. Why? Because the file path "C:\Users\YourName\Desktop" doesn't exist on their computer. It's time to fix this with Parameters.

Power Query is an amazing tool for cleaning data, but it has one major weakness: absolute file paths. By default, when you import a CSV or Excel file, Power Query hardcodes the exact location into the query steps.

This means if you rename a folder, move the file, or send the workbook to a team member, they get the dreaded DataSource.Error: Could not find a part of the path.

The solution is to abstract the file path using a Parameter. A parameter is essentially a variable that you can change easily without opening the Power Query Editor.

The Goal: Instead of asking Power Query to look for "C:\Users\John\Reports\Data.csv", we ask it to look for FolderPath & "\Data.csv".

Step 1: Create the Parameter

First, we need to define the variable that will hold our folder path.

1. Open Power Query (Data > Get Data > Launch Power Query Editor).
2. In the Home tab, click Manage Parameters > New Parameter.
3. Name: `FolderPath`
4. Type: Text
5. Current Value: Paste the path to the folder where your files currently live (e.g., `C:\Data\Sales\`).
6. Click OK.

Step 2: Modify the Source Step

Now we need to tell your query to use this new parameter.

1. Select your query on the left.
2. Look at the Source step in the Applied Steps window.
3. You will see a hardcoded string in the formula bar, like: = Folder.Files("C:\Data\Sales\").
4. Delete the hardcoded text (keep the quotes if adding a suffix, but usually you replace the whole string).
5. Type the name of your parameter: = Folder.Files(FolderPath).

// BEFORE (Bad) Source = Folder.Files("C:\Users\Admin\Desktop\SalesData") // AFTER (Good) Source = Folder.Files(FolderPath)

If you hit Enter and the preview data remains, congratulations! You have successfully dynamic-linked your query.

Step 3: Creating a "Control Sheet" (Excel Only)

If you are in Excel, you can take this a step further. You can let users type the file path into a cell on the spreadsheet, and have Power Query read that cell.

The "Named Range" Trick:

1. Type your file path in cell B1.
2. Name cell B1 `FilePathInput` (using the Name Box in the top left).
3. Import this single cell into Power Query (From Table/Range).
4. Right-click the value inside Power Query and select Drill Down. This converts the table into a scalar text value.
5. Use this query name as your parameter in other queries.

Why This Matters for Collaboration

When you share a workbook set up this way, your colleague doesn't need to know how to edit M code. They simply open the "Settings" sheet, paste their own folder path, hit "Refresh All," and the report works perfectly on their machine.

Pro Tip: You can also use parameters to filter data. Create a parameter called `YearFilter` set to "2025" and use it in your Filter Rows step. This lets you switch reporting years instantly.

Conclusion

Hardcoding is a habit from the past. In modern data engineering, flexibility is key. By spending 2 minutes setting up a Parameter today, you save hours of troubleshooting "broken reports" in the future.

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