Or just decrypt the bitlocker volume from the recovery mode. It would be automatically reencrypted at the next boot.
To decrypt - boot to recovery with CMD, enter bitlocker recovery key, then run the command "manage-bde.exe -off c:"
this would start the decryption process and exit immediately. To check the progress - periodically type "manage-bde.exe -status". Here is the tool command line reference: http://technet.microsoft.com/en-us/l...(v=ws.10).aspx

But in the case if this is a disk corruption - I'd recommend to checkdisk it first from the recovery console ("chkdsk c: /offlinescanandfix").