Hi Maui,
Thank you for posting in Microsoft Community Forums.
As per the description, you want to know whether you have to format the Seagate Backup Plus before partitioning the hard disc.
1. What are the options listed when you right click on the external hard disc? Does it have a drive letter assigned?
2. What does disk management show for the external hard disc? Is it shown as RAW, NTFS or FAT 32?
Every hard drive needs to be partitioned and formatted before it can be used. If he does not have any data on the external hard disc, you may create a new partition and then format the hard disc. If it is already partitioned, then you may delete the existing partition and then create a new one. Delete the existing partition if there is no data, otherwise the data will be lost.
Please follow the steps:
Open Windows 8 Disk Management by pressing "Windows + R" and typing "diskmgmt.msc".
Right click on the hard drive partition (External hard disc Seagate) and select "Format" in the drop-down menu.
In the pop-up window, you can type a partition label; choose NTFS or FAT32 file system.
Do let us know if you have any other queries pertaining to Windows in the future. We will be happy to help. We, at Microsoft strive towards excellence and provide our customers with the best support.