The XLS file format is assigned to the spreadsheets that are created using the Microsoft Excel versions that were published prior to the 2007 version of the product. The later versions of the Microsoft Excel now make use of the .XLXS file format instead of the XLS file extension. This is for the reason that the latest Excel program utilized the XML file format for increased file and program efficiency.
The Microsoft Excel is a vital part of the Microsoft Office suite, though it can be purchased separately. Excel is a program that s generally utilized to create the spreadsheet files, and most of the spreadsheets created today have the .XLSX file format.
In addition to the problem described above, i.e. the lack of the appropriate application to support the .XLS file, there may be several reasons that cause problems with opening and operation of the data format:
A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .XLS file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .XLS file, so download the update and check again.
If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:
It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.