How To Fix Cyclic Redundancy Check Error On External Hard Drive?

The HDD fixing /recovery methods described on this page may cause data loss, so do them only on your own risk.

How to get into WIndows Disk manager? Win. + R, then type and execute: diskmgmt.msc
Make sure HDD is "Online" and Initialized.

If there is Redundancy check error during initialization, you may try HDD fixing steps below.

1. This computer / right click bad HDD / Options / Tools / Error checking / Check now

First try only option "Automatically fix file system errors" (can take minutes to hour). If it do not solve the issue, try option "Scan for and attempt recovery of bad sectors" (can take hours to complete).

2. Win. + S / type: cmd / right click Command line entry and select to run as Administrator.

Once black command line window open, type: chkdsk /F /R /I x:
/F – This switch will fix errors on the external hard drive.
/R – This switch will find and locate the bad sectors on the external hard drive and will also attempt to recover all the readable information.
/I – (I not L) This switch will perform a less vigorous check of index entries.

x: is the letter of your HDD. If HDD is letter D:\ then use "d:" by executing that command chkdsk can do irreversible changes to your HDD data in aim to fix the filesystem. I had an Truecrypt volume encrypted container file on the HDD and because of bad sectors the volume file got irreversibly corrupted (it shown 0 zero size after chkdsk). If HDD contains small files and there are bad sectors, maybe only a few files will get partially damaged. So before running chkdsk, consider backup your HDD data/clone HDD. chkdsk is probably not dangerous tool, but run it at your own risk. It can modify data on HDD.
To maybe reduce damage and scan time, you may skip bad sectors search by removing /R switch from the chkdsk command and if issue is not fixed after scan complete, add /R switch and scan again.
Enter key to execute mentioned chkdsk command. It can take several hours or even overnight to complete. Save the results & google them to get better idea.

3. try to replace data cable or use HDD on another computer

4. If previous methods failed, you can try to quick format HDD and then use data recovery software that may recover some (probably not all) data.
This computer / right click bad HDD / Format ... HDD / Select "Quick format".
Then use software like Recuva, to scan the HDD and recover some files.

5. you have not lost your life, learn to do regular backups and share your experience with others