How to Fix An Unexpected I/O Error Has Occurred Message

Most of the time, This error occurs after inserting a bootable USB flash drive in PC. But, It has other reasons too. Any third party software, viruses can cause this problem. Again, It can be a result of your hardware failure. All of these things make your necessary boot elements corrupted. That’s why windows can’t communicate with these files and shows the I/O error code: 0xc00000e9.

Sometimes, Hard disk problem is also responsible for it. If you have a very old hard disk, You have a good chance to face it. Again, It can be a result of BIOS misconfigurations.

Although there are several methods of resolving the error, a method that works will depend on a specific cause. Below are some of the methods you can adopt. Although a method may apply for a specific OS, it should give you an idea on how to do the same with a different Windows OS.

The simple act of ensuring that all devices connected to your computer are not faulty can easily resolve the error. They should also be connected properly. This is especially important in a case where you are installing the operating system using a bootable disk or DVD.

The first thing you can do is choosing Last Known Good Configuration from advanced boot menu. To do it, Press and hold F8 key from keyboard after switching the power button on when the PC manufacture logo appears on screen. Then, You will see the legacy advanced boot menu. Choose last known good configuration by arrow buttons of keyboard. Then hit Enter. It is applicable for windows 7.

You also should check, If you can boot into Safe Mode with Command Prompt or not. You will need to run chkdsk C: /f command, If you can boot. Sometimes, It may fix unexpected I/O error.

Sometimes, This problem “An Unexpected I/O Error Has Occurred” can be a result of incorrect BIOS settings. You will need to load default configuration of the BIOS firmware.

You may have to rebuild BCD store to do that you will need to boot your PC with Windows Installation DVD. At the Command Prompt execute following command:



If you are lucky, It should fix the boot error.