ISO files are a popular way to backup DVDs, copy CDs and save information from traditional disc media such as physical DVDs or CDs. When a ISO image is corrupted it is possible to lose that data. It is possible to repair an ISO image with the program ISOBuster, which offers a free trial version.
Download and install ISOBuster.
Open ISOBuster and select "File" and "Open Image File" from the topmost menu.
Select the corrupted ISO image you want to repair and click "Open."
Click on the files in the opened ISO file that you want to save and select "Extract."
Click "Save" and the extracted files will be saved to your hard drive. This amounts to repairing the ISO as all or some of its files have been saved. The ISO itself may work. If not, the files are saved and you can rebuild it with any CD-R or DVD-R burning tool.