CD Extra CDs store audio data on the first session and digital data on the second session. Since standard PCs read the second session, audio data on CD Extra CDs can not be imported.
When opening a sound file, MySoundStudio convert the data to the temporary file for editing and save it on your hard disk. If there is not enough space to store this file on your hard disk, MySoundStudio displays this message and can not open the sound file.
To solve this problem, choose File - Settings, click the Temp File tab on the dialog that appears, and set Temporary storage folder: to the other disk that has enough disk space.