Free Fixes for Cyclic Redundancy Check Errors

The Cyclic Redundancy Check (CRC) is a process your computer employs to ensure data is being read correctly from a media source like a CD or DVD or hard drive. The check works by comparing the data being read into memory against the data actually on the disc. If the data fails the check, your computer reports a Cyclic Redundancy Check Error and the data is discarded. There are a few free fixes for CRC errors. Follow these simple procedures.

CRC Recovery

The CRC error occurs when bad data's being read into your system. To repair this, you'll have to restore the data so that it reads correctly. The best way to do this is to restore the file from the source. Whether it’s a network problem, bad media or corrupted storage, the file will be unusable until you correct the underlying causes of the error.

Transmission Fix

If your file was sent over a network, check that the network is working. The CRC error can be caused by a problem during transmission. Anything from a collision of data in the network to packet errors can cause corruption of your file, but this is generally the easiest CRC error to fix. You’ll need to track down the network error and retransmit a clean version of the file.

If you’re certain the network is able to transfer files but the file you receive is still experiencing a CRC error, the problem might be with the file itself.

Corrupt File Fix

Your file may be corrupted. Check the file for corruption by attempting to access it with a different reading program or on another computer. If the file reads on another system or with another program, you’ll know that the data's safe, and you should reinstall the original access program to try again, use the alternate program that was successful to read the data, or, if it’s your system that’s the cause of the problems, examine your hard drive. If the file still gives you an error on the second system or with an alternate program, you’ll need to reacquire a working version of the file from its source.

If the problem is with your hard drive, run scandisk and then defragment your hard drive to fix any errors that might be corrupting your data. If the file is being accessed from an external media source like a CD or DVD, you might have to fix the media before the file is of any use.


Examine the physical media your file is being accessed from for any visible physical damage or dirt. Either causes CRC errors, so if present, repair or clean your media and try again. If it still doesn’t work, try an alternate device, and if it works there, the problem is your own CD/DVD reader, which might need to be replaced. If the data's not accessible after cleaning and is unreadable on a separate device, you’ll have to recreate the storage medium, or acquire the file by other methods.