I have the same problem with a WD My Book Home edition.
I have tried following the instructions for Test Disk but can't get past the Please Wait screen in Test Disk after I hit the enter key (on No Log).
I am running Windows 7 - 64 bit.
I have an external WD 1 TB hard drive connected with USB that is partitioned into drive G and drive H.
H is where my important data is and it is suddently "not accessible" and it wants me to format it to use it. I click NO to that then the box pops up DATA ERROR (CYCLIC REDUNDANCY CHECK).
G still works fine so I know it is not the actual hard drive or cable causing the problem.
Both were formatted NTFS and given a name of WD 1 TB first (G) and WD 1 TB second (H).
G still has it's given name and is still NTFS. H is now just LOCAL disk that is listed as RAW.
I have tried restarting the computer but that does not change anything.
I have tried a cold boot and that brought the drive back so I started a backup and went to bed. Got up in the morning and the backup had stalled out, early on, as drive H went back to being a LOCAL drive that is RAW.
I downloaded both versions of Test Disk and tried to run them as administrator.
I tried the 32 bit first as I assumed I had WoW64 from what I had read.
When that didn't work, (stalled out with please wait after choosing No Log and hitting the enter key) I downloaded and ran the 64 bit version but the same thing happens... I choose No Log, hit the enter key, then am greeted with Please Wait... but nothing ever populates after that and I've waited up to a half an hour.
What do I do next?
thank you in advance for your assistance,