Ubuntu – Can’t Mount External Drive After Reformatting

gpartedhard drivemountpartitioning

I just bought a Toshiba Canvio 2TB external hard drive. I then installed GParted, and reformatted the drive to ext4 (following the instructions in part 1 & 2, at this blog).

The instructions didn't say anything about this, but I think I should've added a boot flag to the drive, 'cause now it won't automount, and GParted won't show the drive, and fdisk -l doesn't even show the drive. So I'm not sure how to mount it or find a way to add a boot flag… if that's even what I need to do.

How do I get to where I can edit the drive's partitions and stuff? Can I format the unallocated 1.02MB on the drive to boot? The unallocated space does show up in GParted. I really hope I didn't just brick this $100.

UPDATE: Here's the output when I sudo fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x0003ae80

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048   969058303   484528128   83  Linux
/dev/sda2       969060350   976771071     3855361    5  Extended
Partition 2 does not start on physical sector boundary.
/dev/sda5       969060352   976771071     3855360   82  Linux swap / Solaris

…the partition I formatted, was something like /dev/sdb or something like that, but it doesn't show up.

Best Answer

Don't worry; your drive is just fine.

When you unmount a drive in Linux (which you had to do in order to format it,) sometimes it won't be re-recognized until you reboot your computer.

Try rebooting, and see if that fixes the problem.

There's nothing that GParted can do anyway that would prevent sudo fdisk -l from noticing the drive. (you did remember sudo, right? ;)

If, for whatever reason, the drive isn't recognized after you reboot, it (likely) wasn't your fault.

After rebooting, if the drive doesn't appear in the launcher, try running GParted again and see if it recognizes the drive. Then check the filesystem on the Ext4 partition (from within GParted.) It'll detect and repair any errors to the filesystem itself. After that, reboot again.

Your partition table is screwed up.

Looking at the output of sudo fdisk -l, I'd have to deduce that your partition table got corrupted. Try opening GParted and going to Device > Create Partition Table, then create a new msdos partition table (the default.) After that finishes, create a new EXT4 partition, but this time tell it to align to Cylinder instead of MiB. (You might lose a tiny bit of space, like .01 GiB tops.)
APPLY the partition creation, then expand the partition to the right, if there's any unused space an that side. (DO NOT move/expand to the left, this will defeat the point of aligning it to Cylinder.)

It seems that the drive shipped with a faulty partition table, which worked with the default formatting (somehow,) but failed when you tried to repartition it.