I did what you suggested - the powered drive is plugged directly into the pi, the others disconnected. Same error message when trying to map the drive.
I am on V4.1.7 (Arrakis).
If I put \\raspberrypi or \\raspberrypi.local or \\192.168.1.225 in File Explorer I just get "this folder is empty"
If I try mapping a network drive using \\192.168.1.225\goflex I get "a device is not functioning" message, if I try just \\192.168.1.225 I get "Windows cannot access \\192.168.1.225"
This is in dmesg
[ 4.652614] brcmfmac: F1 signature read @0x18000000=0x15264345
[ 4.662682] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6
[ 4.663474] usbcore: registered new interface driver brcmfmac
[ 4.690137] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac43455-sdio.txt failed with error -2
[ 4.793510] scsi 0:0:0:0: Direct-Access Seagate FA GoFlex Desk 0D12 PQ: 0 ANSI: 0
[ 4.794651] sd 0:0:0:0: [sda] 3907029167 512-byte logical blocks: (2.00 TB/1.82 TiB)
[ 4.795082] sd 0:0:0:0: [sda] Write Protect is off
[ 4.795096] sd 0:0:0:0: [sda] Mode Sense: 23 00 00 00
[ 4.795633] sd 0:0:0:0: [sda] No Caching mode page found
[ 4.795656] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 4.818821] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 4.866427] sda: sda1
[ 4.869465] sd 0:0:0:0: [sda] Attached SCSI disk
[ 5.692418] brcmfmac: brcmf_sdio_htclk: HT Avail timeout (1000000): clkctl 0x50
[ 12.918058] random: crng init done
[ 12.918069] random: 7 urandom warning(s) missed due to ratelimiting
[ 83.685411] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: user_xattr,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0,acl
[ 93.293157] EXT4-fs (sda1): re-mounted. Opts: (null)
[ 101.980146] EXT4-fs (sda1): re-mounted. Opts: (null)