Hello,

I've seen many threads addressing this problem, but did not find a solution that applies to my situation. I have an out-of-the-box Windows formatted 3TB USB hard drive that I cannot mount. Error msg directly below:

[root@cnl10 ~]# mount -t ntfs /dev/sdc1 /mnt/backup3tb/
NTFS signature is missing.
Failed to mount '/dev/sdc1': Invalid argument
The device '/dev/sdc1' doesn't seem to have a valid NTFS.
Maybe the wrong device is used? Or the whole disk instead of a
partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?

I get the same error with ntfs-3g.

And here is output of fdisk showing only that which applies to the external drive:

[root@cnl10 ~]# fdisk -l

WARNING: The size of this disk is 3.0 TB (3000592977920 bytes).
DOS partition table format can not be used on drives for volumes
larger than 2.2 TB (2199023255040 bytes). Use parted(1) and GUID
partition table format (GPT).


Disk /dev/sdc: 3000.5 GB, 3000592977920 bytes
1 heads, 7 sectors/track, 104652377 cylinders
Units = cylinders of 7 * 4096 = 28672 bytes

Device Boot Start End Blocks Id System
/dev/sdc1 2 104652001 2930256000 7 HPFS/NTFS

Finally, I may have made thing more complicated by following instructions on this page:

geekyprojects.com/ubuntu/how-to-format-a-usb-external-

specifically in the 'Problematic Drives' section, whereby I manually created fat32 partitions, though I'm not sure it actually 'worked' (the error and fdisk output above are unchanged from before attempting this partitioning). If I try to mount specifying fat32 filesystem, I get:

[root@cnl10 ~]# mount -t vfat /dev/sdc1 /mnt/backup3tb/
mount: /dev/sdc1: can't read superblock

If anyone can offer any insight into how I can mount this drive, I would greatly appreciate. There are no data on it since it's new, I had planned on formatting it anyway to use exclusively as a backup to my linux machine. Distribution is CentOS 5.5. Thanks!

What happens if you dont specify the -t option on your mount, this should allow mount to try and auto-detect the fs type. Otherwise we will have to look deeper, if there is no data here we can blow the partitions out and make an ext4 filesystem on it under Linux.

Thanks for the reply. Here's what happens when I don't specify type:

sudo mount /dev/sdc1 /mnt/backup3tb/
mount: /dev/sdc1: can't read superblock

I have no problem wiping out the partitions and reformatting, I am just not sure how to go about it, I thought it was necessary to mount the drive first. Is that not the case?

Another question I have is if I re-partition as ext4, will I be able to read data on other OSs? For example, I would like to be able to read data off the drive using my mac.

Thanks again.

If you have an Ubuntu or derivative Linux CD, it should have GParted on it which will probably be better for you to partition and/or format a drive that size. You should be able to find tutorials online on using it like the one below:

http://www.howtoforge.com/partitioning_with_gparted

AS for being able to see your Linux system from a Mac or vice versa, don't know? I would expect you could but have no idea how that might work as I've never used a Mac.

Guess this is the wrong place to ask mac questions

I'm a bit confused though. Ultimately I want to use GParted, and had tried to but the program did not seem to register the external drive. I thought this was because it was unmounted, so I was looking for ways to mount. But, judging from the tutorial in the previous post, re-partitioning must be done on unmounted drives.

Could anyone tell me then why I do not see my unmounted external drive in GParted?

If I could see it and re-partition it, that would solve my problem. I haven't tried to boot from the live CD, but since its an external it can be unmounted with no problem.

Thanks!