I am trying to make an external backup and wanted to make a partition on my external USB drive for that.But using gparted, I cannot get this done. I connected the drive, unmounted it, but cannot resize(smaller, not bigger ofc) it although there are like 19GB I could use for an ext4 partition.And FYI I am using Antergos(Arch).What am I missing? I don't think this necessarily requires a live linux.
Resizing NTFS partition on USB drive
gparted