RB433UAH Usb HDD Problem

I have an RB433UAH and I want to connect an external HDD.
I’ve connected a 2,5’’ WD 500Gb disk and a 3,5’’ 2TB Seagate external drives.
I can see them in system/stores but I get 0kb total and free space and disk invalid.

Should I do something else?Should I use a clean drive or format the drives through winbox?
Both use NTFS.

Yes, you need to format the disks.
/store disk format-drive command is used to format the disk.

Thanks sergejs for the quickest reply I’ve seen so far…I will do so.
Another thing.Can I use one of those drives to provide some files through my hotspot splash page to the hotspot users (and what would be the links to login.html be like?) or usb-hdds are used just for web-proxy and userman?

sw0rdf1sh, yes you can use second disk for FTP.
There is no too much settings and configuration for FTP policies.