[PROBLEM] How to add local hdd as a music source

[Miss Sissy Princess]

Why I want the USB HDD to be formatted in NTFS? Because it is much easier to copy files between multiple systems (eg. I can take this HDD to my friend which uses Windows on his home computer and let him copy files from me and vice versa)

That's like saying "I want my car to be a Mazda Miata because they are so convenient for hauling major appliances and building materials."  NTFS is one of the worst filesystems for portability.

Reformat the USB HDD to FAT32 or exFAT with a Master Boot Record partition map.  Everything from macOS to Linux to Windows will be able to copy files to and from it.  

Note: I realize that this is an old thread, but I'm not the only one who will come across it in a search.