The XLSX format is a Microsoft Excel 2007 format that is not compatible with older versions of the said application. Luckily, there are alternatives to converting a 2007 Excel document to an older version of it. I prefer the online way but there is also a compatibility pack for MS Office that does the trick. The format is currently not supported by GMail attachment viewer or any of the online office suites like Google Docs so you have no choice but to have it converted to an old format else you will not be able to view it.

Likewise, with the adoption of support for XML in Microsoft Office 2000, developers began to see the need to transition from the binary file formats seen in previous versions of Microsoft Office to the XML format. Binary files (.doc, .dot, .xls, and .ppt files), which for years did a great job of storing and transporting data, were not able to meet the new workplace challenges that included easily moving data between disparate applications, and allowing users to glean business insight from that data.

The 2007 Microsoft Office system continues with this transition by adopting an XML-based file format for Microsoft Office Excel 2007, Microsoft Office Word 2007, and Microsoft Office PowerPoint 2007. The new file format, called Office Open XML Formats, addresses these workplace issues with changes that affect the way that you approach solutions based on Microsoft Office documents. The new formats improve file and data management, data recovery, and interoperability with line-of-business systems. They extend what is possible with the binary files of earlier versions. Any application that supports XML can access and work with data in the new file format.

XLSX Converter to Convert XLSX to XLS. You can easily convert .xlsx spreadsheet to the traditional .xls format using the Microsoft Office compatibility Pack available. It will help you open, edit, and save .xlsx files in Office 2000, Office XP, or Office 2003. Besides the following software can help you to convert .xlsx file to .xls

Best XLSX to XLS converter software

Xlsx Xlsm to Xls Converter 3000

If your computer is compatible Office 2003, but you want to make use of the Office 2000/2007 Excel. Now,I recommend a very excellent xlsx to xls converter - Xlsx Xlsm to Xls Converter 3000. It can help you free batch convert xlsx, xlsm to xls with professional quality and fast speed. User-friendly interface allows you to use very easily withoutany learning curve. Merely need a few clicks. Add the converted files to the list and click "convert" conversion can be done automatically.

Xlsx Xlsm to Xls Converter 3000 Advanced features: Simultaneously convert massive different format files to Xls once; Convert Xlsx,Xlsm to Xls; Provide more detailed parameters settings to resize the output page; Support add the entire folder to convert. User-friendly interface, very easy to use, just a few clicks can finish the conversion. Xlsx Xlsm to Xls Converter 3000 Download

Batch XLS and XLSX Converter

Xls to Xlsx and Xlsx to Xls Batch Converter. Xlsx to Xls & Xls to Xlsx Batch Converter convert Excel 2003 to/from Excel 2007.

Batch XLS AND XLSX Converter is a Excel XLS to XLSX, XLSX to XLS Batch Converter that can convert Excel XLS to XLSX and XLSX to XLS easily. Batch XLS TO XLSX Converter supports powerful search for a lot of files. A XLS and XLSX converter for Excel.

Batch XLS AND XLSX Converter supports project and command line. Batch XLS AND XLSX Converter has a friendly GUI so it is used very easily. Batch XLS & XLSX Converter Drag and Explorer Context supported.

Batch XLS AND XLSX Converter supports a efficient Multi-Thread conversion engine. So you could control the conversion action very easily. You can stop or pause and continue it in any time. You can save your conversion work in a project file (.batch-xls2xls) for re-use. You can run the batch-xls2xls project in Microsoft Windows Explorer or command line directly. Batch XLS and XLSX Converter Download

ByteScout Spreadsheet Tools

I find ByteScout Spreadsheet Tools is a wonderful software to convert XLSX to XLS. This wonderful software can converts XLS, XLSX, ODS, CSV files into HTML, PDF, CSV, XLS, XLSX files in a batch WITHOUT installing Excel or Office. 12 months of free updates and 12 months of free tech support via e-mail (within 2 business days) are included.

ByteScout Spreadsheet Tools supported input formats: XLS, XLSX (Excel 2007), CSV, ODS (Open Office), TXT (tab-delimited). This software supported output formats: HTML, PDF, XLS, XLSX (Excel 2007), CSV, TXT (tab-delimited), Excel or other spreadsheet software is NOT REQUIRED! ByteScout Spreadsheet Tools also support batch conversion support. ByteScout Spreadsheet Tools Download

office Convert Excel to Pdf

Now I recommend a wonderful software to you - office Convert Excel to Pdf! It can import rtf,txt, excel(xls,xlsx,xlsm) to the popular format-PDF(as default format, as image format, as text format) without losing any the original Text, Tables, Graphics & Layout.

office Convert Excel to Pdf allows multiple pages are converted at a super-fast speed which means that even the longest files will be converted very soon, minutes even seconds. More, it has exclusive functions as it can support the input xls sheets combined to convert and so on.

The easy-to-use interface of office Convert Excel to Pdf only allows you to create PDF files by simply click the "Convert" button. The Converter includes PDF options as Top, Bottom etc .It accurately retains the layout of the original document file. office Convert Excel to Pdf Download

Sunflower Excel .Net

Sunflower Excel .Net is another excellent XLSX converter that I recommend. It is a non-graphical component that enables in windows applications to convert Excel Spreadsheet XLS to HTML . It also supports converting XLS files to other Microsoft Excel(R) files such as CSV, TXT, XML, XLSX (only for Microsoft Office(R) 2007). The component requires Microsoft Office(R) installed.

Sunflower Excel .Net converts source files with tables, graphs, images, hyperlinks, fonts etc. The component is very easy to use and is provided with 2 fully featured demos written in both C# and Visual Basic. It also allows you to create your own windows applications that will be able to convert one or batch of Excel files.

Sunflower Excel .Net support file formats: XLSX to HTML, XLSX to CSV, XLSX to XLSX, XLSX to XML, XLSX to TXT, XLS to HTML, XLS to CSV, XLS to XLSX, XLS to XML,. XLS to TXT. It can convert Excel files to different formats TXT/CSV/HTML/XML/XLSX. Sunflower Excel .Net Download

Xls/Xlsx to Pdf Converter 3000

Xls/Xlsx to Pdf Converter 3000 is an easy-to-use and flexible PDF converter. It can free batch convert Excel xls,xlsx format files to professional-quality PDF with high conversion speed. Now, you can view your Excel with a PDF viewer. It is easy to use with merely a few clicks can finish the conversion without any learning curve. It is standalone software.

Xls/Xlsx to Pdf Converter 3000 Advanced features: Simultaneously convert massive different format files to PDF once to save time and energy; Do not need any printer driver and Adobe Acrobat, Acrobat Reader etc software; Support xlsx of Office 2007; Create PDF file from xls/xlsx format files with three modes (default mode, image mode, text mode) for different needs; Merge each sheet of Excel to one PDF; Provide watermark image settings and watermark character string settings. Xls/Xlsx to Pdf Converter 3000 Download