Issues opening XLS (2007) documents in Office Excel 2013 (Network Steve Forum)

Issues opening XLS (2007) documents in Office Excel 2013

I recently upgraded my computer from Windows XP/Office 2007 to a completely new computer with Windows 8.1/Office 2013.

I am unable to open any of my .xls spreadsheets. The error I am getting from Office 2013 is:

"The file format and extension of "Blank Once and Again Invoice.xls' don't match. The file could be corrupted or unsafe. Unless you trust its source, don't open it. Do you want to open it anyways?"

And when I choose to open it anyway, my spreadsheet is full of giberish/symbols/nonesense.

My friend with Office 2010 is getting the same error and code. Is there a way to recover my files? Please help me save my business data!

July 6th, 2014 12:39pm

Hi,

Please try the following method.

Excel 2013:

1. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Excel\Security

2. Edit --> New --> DWord value

3. Name it ExtensionHardening. It will be on 0 by default.0

The file has to have an XLS extension, the key won't work for XLSX and the file wouldn't open using it.

    Key: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Excel\Security
    Value: (DWORD)"ExtensionHardening" = [0 = Disable check; 1 = Enable check and prompt; 2 = Enable check, no prompt deny open]
    Default setting if value not present is 1 (enable and prompt).

Quote From:

http://social.technet.microsoft.com/Forums/office/en-US/fff5ef8e-d330-4035-974f-a2d5655cbe83/excel-2013-extensionhardening

Regards,

George Zhao
TechNet Community Support