Time machine not recognizing drive

have a Lacie external backup for a Time machine. I also use it for the Win7 backup on the same drive. Mountain lion does not recognize the drive. I can see it ,but it is not mountable. I have done the verify and repair disk, but it does not complete it before it kicks out. In Win7, I can see the drive and files on it. I can see the Apple backup files, but can't in Mountain lion. What can I do to get mountain lion to see the hard drive and use it for my time machine again?

Thanks

G'day and welcome to the forums.

Question 1 is it formatted Mac OS Extended? If not you may have to partition the drive and format. IMHO the best way is to have separate hard drives for backing up Windows and Mac OS X.

Yes, the drive is formatted OS extended.

Thanks