Back-up hard drive no free space eror. Hi I have a Seagate 80GB external hard drive for back. It

Question

Hi I have a Seagate 80GB external hard drive for back. It had been working fine. I had to update unattended back-up and reset through the bounce back centre. I deleted the old back-up files on the external hard drive to start of fresh. Created new back-up Now when the back scans, it comes up with an error saying the is not enough space, yet they is easily the capacity. Should I reset the drive somehow? Cheers Paul