XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.
This month's monster security patch for Office breaks Excel when it tries to open HTML files, and it seems unlikely Microsoft will fix the problem Excel users are reporting an odd bug in the way Excel ...
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Excel security is a myth: Passwords and hidden rows won't save your data, but this will
From hidden rows to sheet protection passwords, Excel's "privacy" features are easily bypassed—encryption and deletion are much more watertight.
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