You're here because you have a file that has a file extension ending in .cdf. Files with the file extension .cdf can only be launched by certain applications. It's possible that .cdf files are data files rather than documents or media, which means they're not meant to be viewed at all.

The CDF in files with the .cdf extension stands for computable document format, and this file format was developed by Wolfram Research as a multimedia encoding standard of interactive documents that can contain different text formatting attributes and multimedia elements. These multimedia elements are mostly visual objects like charts and graphs that can also be integrated with interactive functionalities, which can be done through features provided by the CDF Player software. Files appended with the CDF extension can be created, opened and accessed using the CDF Player software. Microsoft Windows-based systems with this software can also view the content of these CDF files for further editing, and there are CDF Player versions provided by Wolfram Research for Linux and Mac platforms. The Wolfram CDF Player plug-in software can also be installed in a Microsoft Windows-based system to implement support into standard Web browsers for opening and viewing the content of these CDF files. This plug-in software also has versions for Linux and Mac systems. Some mobile platforms with support for these standard Web browsers may also have support for these CDF files.

Launch a .cdf file, or any other file on your PC, by double-clicking it. If your file associations are set up correctly, the application that's meant to open your .cdf file will open it. It's possible you may need to download or purchase the correct application. It's also possible that you have the correct application on your PC, but .cdf files aren't yet associated with it. In this case, when you try to open a .cdf file, you can tell Windows which application is the correct one for that file. From then on, opening a  .cdf file will open the correct application. Click here to fix .cdf file association errors

Be careful not to rename the extension on .cdf files, or any other files. This will not change the file type. Only special conversion software can change a file from one file type to another.

A file extension is the set of three or four characters at the end of a filename; in this case, .cdf. File extensions tell you what type of file it is, and tell Windows what programs can open it. Windows often associates a default program to each file extension, so that when you double-click the file, the program launches automatically. When that program is no longer on your PC, you can sometimes get an error when you try to open the associated file.