error ed800012

I am using ghost 15 updated to the newest service pack on win7 64 bit and a 3TB usb external hard drive formatted ntfs. I've read some other posting on this issue and tried changing compression, but I keep getting this error. It seems as though the entire backup is created and then when it goes to verify the recovery point, it runs into this error. This is the first backup and the first time I'm using the exernal hard drive. Help please.