When you try to boot into Windows on your SSD or normal HDD, you see an error message that reads – A disk read error occurred. Press Ctrl + Alt + Del to restart. This can also happen when you try to boot into a bootable USB flash drive.
“A disk read error occurred” can happen when you boot to your SSD, HDD, USB flash drive or any other bootable media, regardless if the media has a Windows 10, Windows 7, Windows 8 or Windows XP operating system. It can also happen on laptop or notebook from various manufacturers such as HP, Toshiba, Dell, Asus and Acer.
Sometimes the A disk read error occurred comes with other errors such as bootmgr is compressed, error code c00000b5 and c0000185 which can happen during upgrade or installation of Windows or other OS or software. In rare occasions when you try to create virtual HDD into VMware virtual machines using Disk2vhd, a disk read error occurred may also appear.
Fix: A disk read error occurred Windows 10
Understanding the problem
The a disk read error occurred message means that your computer is unable to read the disk which your BIOS set to boot first due to disk error. Many different reasons can trigger this particular boot error. There is no guaranteed fix for this problem, but most of the time it indicates a hardware error.
Here’s what you can do to troubleshoot the error and to verify if it is or not a hardware issue.
Unplug all USB drives, DVD and other external media
Unplug any USB flash drive from your PC and remove DVD from the player. Then, try to boot your computer again.
This is to make sure your computer isn’t booting into a drive that is not what you want to boot. For example, you want to boot into your hard drive where your Windows was stored, but the BIOS boot priority is set to boot USB drive first. In that case, when a USB drive is plugged and found by the chip, it will boot to it first and may result in the A disk read error occurred error if the USB isn’t a bootable drive or if it is simply broken.
Alternatively, you can check the boot sequence on your BIOS by pressing DEL or F2 as soon as you start your computer. Then look for a setting usually called Boot Sequence or Boot Priority. Make sure the desired drive is selected to be boot first.
If your intention was to boot into a bootable USB flash drive in the first place and the computer shows a disk read error occurred, it implies that either the USB bootable wasn’t setup correctly or that the USB flash drive is broken. Try to use another software to create the bootable USB drive.
Switch off your computer and let it cool down
I’m sorry to have to say this but most of the time when you see the A disk read error occurred error upon booting your PC, it signifies that your SSD or HDD has failed or starting to fail.
If you’re lucky, a long rest for your PC and the HDD can temporary bypass the error. Abnormally high temperature in your hard disk drive may stop it from working and causes the A disk read error occurred error upon booting.
Thus, try to shut down your computer and let your HDD cool down for a few hours before rebooting it. When you can finally boot into your Windows after cooling it down, backup all important files and whatever else you can as soon as possible. When the HDD gets hot again, it may trigger the same or other disk errors. In this situation, it’s highly possible that the HDD may fail at any point of time and when that happen you won’t be able to boot to it ever again.
Try to replace the hard drive’s cable
Faulty or loose hard disk drive’s cables can also cause the A disk read error occurred error. Check if the HDD cable is fastened on both ends. Also, try to replace the it with a spare HDD cable. If you don’t have a spare HDD SATA cable, you can temporary remove the cable from another computer and test it on this problem computer.
“A disk read error occurred” appears randomly
If the error appears randomly which sometimes you can see the Windows 10 loading logo but unable to boot into it, try to force boot into Windows Recovery Environment. You can do this by long pressing and holding your computer’s power button until it’s completed turned off. Boot it up again and repeat the force shut down for 3 times.
If you can boot into Windows Recovery, use the command prompt tool to run CHKDSK command to check your HDD or SSD for disk error. Besides, you can also run bootrec commands to repair the master boot record (MBR) which directly affects how disk reading works in Windows 10. For more info about how to do this, read – how to startup repair Windows 10 using command prompt.