If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

Twitter used to provide CSV exports of your data, now it's all in machine-readable JSON. How can you use it in Excel?

Don't manually re-enter data you find on the Web. Open Excel and transfer the data directly into a worksheet.

Step 2: Go to “Open”. Note: Select Open from the Office menu in Excel 2007. Step 3: Select the file you wish to fix and open it by selecting “Open and Repair…” from the Open drop-down menu.