WD6400H1U-00 can't be recognized by my computer

Two external drivers of WD6400H1U-00, which were doing well for a long time, could not be recognized by my computer with “Window 7” today. It has never happened before. 

When I plug in my external, the computer makes a sound. I can “Eject my book” at the right corner of the toolbar, but I just could not see the hard drive listed in my computer. I went to “Disk Management”. A window of “Initialize Disk” pops up. Then I could see the disk (Unknown and Not Initialized) in Disk Management. I right click the Properties of the disk. It shows “The device is working properly. Status: Not Initialized”. 

Does anyone know what happened to my externals? How can I fix it? There are full data in those two hard drives. 

Many thanks.

Hello,

If the computer is asking to initialize the disk it means the partition is corrupted. If you initialize the disk it will delete all the data stored on it. If you need to recover the data I recommend using a data recovery software.

Thanks for reply.

I tried Testdisk last night after doing research on line. However, it says “Read error”, the disk could not be initialized. Today I opened the WD case and took the hard drive out and plugged it into the external dock, but still the same result. Looks like the disk is totally dead. How can I do with this hard drive? Is there a way to recover data?

Thanks so much.