Forum Discussion
Prevent data refresh error when column headers change or are removed
I've run into a similar issue when working with dynamic Excel imports in Power BI. One approach is to use Power Query's Column Renaming Mapping to create a lookup table. You can maintain a reference table with expected column names and apply a transformation to match them during the import process.
For missing columns, you can modify the Transform Sample File step in Power Query and use Table.AddColumn to add placeholder columns when they’re missing. Another option is to Table.SelectColumns with MissingField.UseNull to allow Power BI to ignore missing columns rather than failing the refresh.
Since you're working with a folder source, make sure the Combine Files function is properly set up to handle schema variations. Also, if new files aren’t appearing, check whether the Transform File from Folder step is filtering out certain files due to unexpected metadata changes. You might need to review your applied filters and remove any that restrict data import.
I've run into a similar issue when working with dynamic Excel imports in Power BI. One approach is to use Power Query's Column Renaming Mapping to create a lookup table. You can maintain a reference table with expected column names and apply a transformation to match them during the import process.
For missing columns, you can modify the Transform Sample File step in Power Query and use Table.AddColumn to add placeholder columns when they’re missing. Another option is to Table.SelectColumns with MissingField.UseNull to allow Power BI to ignore missing columns rather than failing the refresh.
Since you're working with a folder source, make sure the Combine Files function is properly set up to handle schema variations. Also, if new files aren’t appearing, check whether the Transform File from Folder step is filtering out certain files due to unexpected metadata changes. You might need to review your applied filters and remove any that restrict data import.