|According the the Seagate link below that drive came with NTFS for Mac pre-formatted.|
The 32GB partiton that is formatted and active is a FAT32 partition. So, did you repartition the drive at some point? I am trying to figure out how you ended up where you currently are with a 32 GB FAT 32 partition and the remainder UN-allocated.
I think you may have deleted all partitions (probably only one there) and then created the FAT32 partition, which Windows would only allow to be 32GB in size. That is by Windows design.
If you don't need the 32GB files you could delete that partition and then create one partition using all available space then try using testdisk to reconstruct the partition, which should have been formatted NTFS.
The problem with doing that is there is no going back to what you have.
If this were my problem, I would get another hard drive, either external or internal and clone the current external drive. Then use that drive to experiment.
Another suggestion is to try posting on the Seagate help site. You could link to this thread or start explaining all over.
Sorry I am not solving your problem. In the future you should ALWAYS maintain at LEAST two verified copies of any files that are irreplaceable.
I am not giving up trying to help. BTW, I did remove the best answer indication so others might join in here. I am a Moderator on this site.
The software that Seagate pre-installed is not something I know anything about. Backup programs usually use compression of some sort to conserve storage space. That is usually done so there is no duplication of data but I don't know what Seagate does. That could be the reason you can't seem to recover files with content.