You may not be able to bring in Excel (.xls) files via Power BI for multiple reasons. Below are some common causes and possible solutions:
Incompatible File Format: Power BI supports .xlsx files more than .xls files because of obsolete features or file structures. Though .xls will still work, it could fail sometimes. So, if you are using a .xls, convert it into the .xlsx format easily by opening the file in Excel, clicking save as new .xlsx file, and importing that one.
Corrupted File: The file itself may be corrupted, especially if you've had difficulty opening it. If it may be corrupted, open the file with Excel and run a check for errors or damaged components. You can also try a file repair, open it with Excel, and use the 'Open and Repair' option in the dialog.
File Size and Complexity: Power BI sometimes does not like very large .xls files, especially those that hold complex formulas, macros, or embedded objects. If the file is heavy, try to lighten it by deleting irrelevant data or formulas. Otherwise, split the file into smaller portions and import them separately.
Excel Add-ins or Macros: The fact that your Excel files may have custom or specialized Excel add-ins or macros would mean that Power BI may not be able to read these during the importation. Delete or turn off the macros and the add-ins, save the file, and import again.
Version and Updates of Excel: Ensure that your Excel is a supported version. Sometimes, files created on a newer version of Excel or using a non-standard format cannot be opened through Power BI. Ensure you update both Power BI and Excel to their latest versions to avoid compatibility errors.
Power BI settings or permissions: Power BI Desktop should have permission to access the file. If it is on a network drive or in the cloud, check if you're permitted and that the path is accessible by Power BI.
Once these important points are resolved, you should be able to import .xls files successfully to Power BI. If none of this works, use the Power Query Editor to clean or troubleshoot data before using Power BI.
