The first thing you should do here is to close all programs that are using the Excel file you are attempting to open. Please ensure the .xls file is not opened in other workbooks, add-ins, or apps.

Cannot open Word, Excel, PowerPoint files or email attachments in Office In such cases, Office may report the file as being corrupt. The exact errors may include: ...

Here’s how to use this feature to fix the “ Excel file extension not valid ” issue: 1. Open Microsoft Excel and go to the File tab . Then, select Open > Browse. Excel file opening options. 2. Find and ...