Alexander’s Blog

Have you run into a situation where you try to access your USB hard drive and get the following error:

E: is not accessible. The parameter is incorrect.

where E: is the drive letter of your external USB hard disk.

You may also get the access is denied error. The drive remains inaccessible even if you try to hook it up to other computers.

A friend of mine ran into this situation and got a quote of $500-$800 from various local data recovery companies in the Seattle area. When she brought the 3.5″ external 320GB Seagate USB drive to me as a last ditch effort before coughing up hundreds of dollars, the first thing I did was connect to my Windows 7 computer to see what kind of error I would get. I was able to see the drive but got the Access is denied error. I decided to use the CHKDSK utility. I figured if that didn’t work then I will look into using some software that can possibly repair the drive because I assumed there were lost clusters, or other disk errors that were making the drive unreadable.

I ran CHKDSK G: /F /R /X, where G: was the drive letter for the USB external drive on my computer.

/F fixes the error on the disk

/R Locates bad sectors and recovers readable information

/X Forces the volume to dismount if necessary

You could also run CHKDSK without the /F parameter to see if there are corrupted files before fixing them. Then you can run CHKDSK with /F parameter to actually fix the lost clusters, along with /R parameter to locate the bad sector and recover readable information from the hard disk.

It took several hours but luckily CHKDSK found about 1.6GB of data in over 5000 recovered files. I let CHKDSK convert the lost chains to files , fix cross-linked files by copying them to other locations, and rename the duplicate files in the folders. I was able to recover almost all of the data (about 5oGB, with over 40,000 files), except for 8 files. I reformatted the drive with NTFS, which is much more reliable and secure file system than the original FAT32.