Can't see m.2 Windows drive in file manager

Running 14.04.2, 4.0 kernel, on ThinkPad T440s, and can't see the m.2 Windows drive. It's definitely there (sdb2 according to fdisk -l; see below). Not sure how to make it visible in Nautilus.

When I run Disks the drive shows up as sdb and a partition as sdb1, but partition type is "unknown" --

Ideas?

$ sudo fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000b4300

   Device Boot Start End Blocks Id System
/dev/sda1 * 2048 499711 248832 83 Linux
/dev/sda2 501758 1953523711 976510977 5 Extended
/dev/sda5 501760 1953523711 976510976 83 Linux

Disk /dev/sdb: 256.1 GB, 256060514304 bytes
255 heads, 63 sectors/track, 31130 cylinders, total 500118192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x9bd54a7d

   Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 3071999 1534976 7 HPFS/NTFS/exFAT
/dev/sdb2 3072000 467980287 232454144 7 HPFS/NTFS/exFAT
/dev/sdb3 467980288 500115455 16067584 7 HPFS/NTFS/exFAT

Disk /dev/sdb1: 256.1 GB, 256060514304 bytes
255 heads, 63 sectors/track, 31130 cylinders, total 500118192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x9bd54a7d

     Device Boot Start End Blocks Id System
/dev/sdb1p1 * 2048 3071999 1534976 7 HPFS/NTFS/exFAT
/dev/sdb1p2 3072000 467980287 232454144 7 HPFS/NTFS/exFAT
/dev/sdb1p3 467980288 500115455 16067584 7 HPFS/NTFS/exFAT