The conversion will fail because of program damage or special codec in the files you want to convert.
1. Please make sure you are using the latest version of the software. You can download the latest version from our official website: www.aiseesoft.com.
2. Please make sure the files play well on the computer.
3. Check if the files play well on the program when preview. If not, there may be special codec in the file.
4. Choose output format for conversion.
If this doesn't work, please contact us with a copy of one file and the output Profile Settings you choose.