Files with the extension CDA usually contain no data in the true sense. They merely represent links to the individual tracks on an audio CD and can only be played by one of them.
The audio data of a CD when copied from the AudioCD is usually contained in wav or aif files. It is not enough to copy the CDA file to the computer. To copy the actual audio data, you need special software.
Most often resolving problems with opening CDA files is very simple. Just install an appropriate program that supports such files. All of the listed programs support CDA files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of CDA files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate CDA files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the iTunes applications is not on the list, select "Browse" option in order to manually locate the directory where iTunes has been installed.
Sometimes problems with opening CDA files may not lie with the application itself, but can arise due to other causes, such as: