Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Last week on my laptop fair few files got corrupt. I cannot rename them, copy them or delete them. Files belong to visual studio so I cannot compile some of my projects, which I need to finish by tomorrow. I get I/O device error. I have had similar issue about a month ago and running check disk utility seemed to fix it. Last time it ran for 3-4 days and on day 4 it got stuck at step 2 of the CHKDSK half way through but once I restarted my PC it had fixed all issues.

Now I am having the same issue, however this time I have had my CHKDSK running for 2 days now and it just got stuck on file 350,064 of 386,050 and hasn't progressed any further for 2 days. I tried to restart like last time but it didn't fix my files. I wonder what is wrong and why it gets stuck. Are there any other good FREE check disk utilities I can use or other switches with chkdsk that I should be trying (if so, how do I do that)? Thanks

share|improve this question
Welcome to Super User! This sounds like a damaged harddrive, which should probably be fixed before worrying about the filesystem. I highly recommend you back up the entire contents to a new disk as fast as possible. I/O errors usually mean the drive controller is damaged, or the platters are scratched / bad / dying / dead. You'll want to look for a tool which can image drives with bad sectors (so it doesn't hang like CHKDSK is), but I'm afraid our Q-A style is not a good fit for software recommendations. You can try the Super User Chat though! Best of luck with your files. – Darth Android Aug 6 '12 at 22:52
@DarthAndroid - what are the good applications that do disk imageing with bad sectors? – fenix2222 Aug 6 '12 at 23:53
Clonezilla has a -rescue option which will handle bad sectors properly:… – Darth Android Aug 7 '12 at 1:42
@DarthAndroid - Is it possible to only recover selected files, rather then entire drive? Most of my data is already backed up elsewhere and I only wnat to recover few hundred files only not the whole 500GB hard drive, which is almost full? – fenix2222 Aug 7 '12 at 4:00
You might try with a linux live CD, but generally no, it would be quite difficult if the files in question have bad sectors, because recovering them requires the FS to be mounted, and there's a good chance that FS drivers don't handle bad sectors properly (most software doesn't, in fact, just because it's such a rare edgecase to worry about). The easiest way to recover a few files is to clone the disk temporarily, recover the files, and then erase the clone. – Darth Android Aug 7 '12 at 14:45
up vote 3 down vote accepted

This sounds a lot like you have a damaged hard drive, which is probably what caused the corruption in the first place. When a program tries to read a bad sector on a disk, it will fail, causing the disk to attempt to read it again. If the application is not designed to time out the reads and move on, they can get stuck forever.

Because very few programs, including filesystem drivers, are designed to deal with bad clusters in this manner, recovering the data is problematic.

If you just need a few files, you can try booting the system up with a linux livecd, and then mounting the disk as read-only and disable integrity checks. As long as the critical filesystem structures and the files you want are on good sectors, you should be able to recover them - from there, you can just discard the harddrive and replace it with a new one and reinstall everything.

If you don't have a good backup or the filesystem is damaged, it'll probably be easier just to re-image the data onto a new drive. You'll need a tool like dd-rescue or CloneZilla running with the -rescue option (or any of a number of other tools which are designed to handle this) to make a clone or image of the bad disk and write it out over the network or to another disk on the system. Once the data is on a properly working disk, you can then attempt proper repairs on the filesystem and recovering your files.

share|improve this answer
Thanks, I will try this – fenix2222 Aug 8 '12 at 0:35

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.