Why won't my 2006 iMac backup to second Lacie Drive?

Hi,

I have two drives for backups but recently have only been using the one as the second drive contains a iPhoto library file that i had to keep.

Now however, i have copied that file (243.8GB), erased the drive and then using Time Machine tried to make a backup of my computer but it fails, telling me it may be temporary and to try again. And i have but it still fails. I've verified it and it passed every time. It's a Lacie Porsche Design, 2TB external HDD.

It's about 8 years old but both only get used about once a month.

The whole backup is 715GB but it doesn't get past 40MB.

It says to repair the disc but it comes back fine.

It's a late 2006 Intel iMac which is having major problems of its own but it has been backing up no problem to the first drive.

**I've just formatted it to OS Extended - Case Sensitive - journaled and it's at 2.45GB and climbing**

Any help appreciated.

Thanks.