I recently updated a project to use PHPExcel 1.74
Now one of the people that frequently runs reports created with PHPExcel can't open files.
I can open the files using OpenOffice Calc 3.21, another computer using Excel 2007 ver 12.0.6535.5002 can open the files.
But, this one person, using Excel 2007, 12.0.6425.1000.
The error message is:
Excel found unreadable content in 'filename.xlsx'. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes.
Click no and nothing happens. Click Yes and the error message is:
Excel cannot open the file 'filename.xlsx' because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.