Background
While using the Power Query function in Excel, I encountered the error: “[Expression.Error] The column ‘Column1’ of the table was not found.”
In this article, I will introduce how to handle this error.
Causes and Solutions
The following causes are considered likely:
1. Column Name Changed or Deleted
Cause: The column ‘Column1’ may have been renamed or removed in the middle of the query steps. Solution: Trace back through the steps in the Power Query Editor to find exactly where ‘Column1’ was lost or renamed.
2. ‘Column1’ Does Not Exist in Source Data
Cause: The original data source (such as a CSV file) referenced by the query might not contain ‘Column1’. Solution: Check the original data source file to ensure the column exists and the name matches exactly.
3. Column Headers Not Set Correctly
Cause: If column headers were not set correctly when importing a CSV file, Power Query assigns default names (e.g., Column1, Column2). If you later changed a setting to “Use First Row as Headers,” the reference to “Column1” might break. Solution: Review the “Promote Headers” step.
4. Incorrect Order of Query Steps
Cause: Due to the order of transformation steps in Power Query, a step might be trying to reference ‘Column1’ before it has actually been created or after it was removed. Solution: Review and reorder the steps if necessary.
Troubleshooting Tips
Identify the Step Where the Error Occurs
Check each step in the Power Query Editor one by one to pinpoint exactly which step triggers the error.
Check the Change History (Applied Steps)
Use the “Applied Steps” section on the right side of the Power Query Editor. Click through the steps to see the state of the table at each point and correct the problematic step.
Re-verify the Original Data Source
Double-check the data source used for the query. Ensure the necessary columns exist and the format is correct.
I hope this serves as a helpful reference. Thank you for reading to the end.
