What Does a Disk I/O Error Mean?

A disk I/O error happens when a computer is unable to perform an input/output action (such as reading or copying data) when it is trying to access a drive or disk. This is often an indication of a drive's failure.

If there is no CD in the computer and you are getting a disk I/O error as the computer is starting, it is possible that your computer's hard drive is failing, or the hard drive's connectors are loose. An I/O error can occur with different types of hardware devices or media, such as external hard drives, SD cards, USB flash drives and CD or DVD drives.