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.

One of the most effective ways to protect your Excel data from unauthorized access is by encrypting your entire workbook with ...

Jeff Hudgins removed the hard drive from a dying computer, and via USB plugged it into a new PC. But he can't access his files. They're encrypted.

Google Sheets Excel security In a Google Workspace update blog post announcing the news, the company noted that the conversion will give the new Google Sheets file client-side encryption.

It uses end-to-end encryption so that not even Apple can access encrypted files. In response to the order, Apple is expected to simply stop offering Advanced Data Protection in the UK.