Spreadsheets created in different versions of Microsoft Excel have a number of properties that can make it difficult to open files. It is worth understanding why files do not open in Excel.
Compatibility issues
Most often, problems with opening files created in Excel are due to the fact that they were created in different versions of the program. If the file was returned in Excel 2007, 2010 and 2013, then it is unlikely to open normally in older versions of the program. The problem may be solved by installing a special patch created specifically to solve such compatibility problems. It is called the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. The number 2007 may sound in the name, but there is no difference between files created in Excel 2010 and 2013, so this patch is ideal for solving problems with opening files.
There is a free program that is in no way inferior in functionality to Microsoft Office and, in particular, Microsfot Excel. It's called OpenOffice.
If it is not possible to install this patch for Excel 2003, you can ask to re-save this file from the new format ("xlsx") to the older one ("xls"). In order to do this, in Microsft Excel 2007, 2010 or 201, you need to click the "File" button, then click on "Save As", and then select the required saving format from the proposed formats.
Formulas and Editing
Microsoft Excel 2007, 2010, and 2013 have a number of significant advantages over older versions. First, it is protection against cyclic formulas. This is a logical error, during which the cycle in the formula will repeat itself indefinitely. In the old version of Excel, such a formula could lead to data loss and system freeze altogether. More recent versions of the product from Microsoft may block the occurrence of such formulas, such files cannot be opened in later versions of Excel. If you need to open the file, you will have to ask its creator to remove all circular formulas from the file.
A file created in newer versions of Excel can open correctly not only with a special patch, but also with the support of all the fonts with which the file was created. Otherwise, you will have to find out their names and download from the official Microsoft website.
It should be said that Microsoft Excel 2007, 2010, and 2013 have formulas that will not be supported in older versions. Such a file may open in them, but not all formulas will work.
Programs that create files for Excel
At the moment, many programs offer the option of saving a file in xls and xlsx formats. Some do it worse, some do it better. For example, the well-known program FineReader is able to scan files directly into Excel format in fairly good quality. These files will be easily opened in any version of Microsoft Excel. But there are many other programs that are not capable of doing this with the same quality. These can be either FineReader analogs or programs specializing in converting files from format to format. Files created in such programs cannot always be opened with good quality in Microsoft Excel.
