Vanishing disk

[Robin Bignall]

I have a 500 Gb external USB disk. In W7 Ult it is recognised as a disk,given
a drive letter and works fine. In W7 Home Premium on my wife's laptop, it comes
up as a disk icon in 'Printers and Devices', has no drive letter, and apparently
cannot be read or written to. 'Properties' say it's a disk and a USB mass
storage, and is working perfectly. We want to use it as a backup device but
appear to be stymied. Any ideas about this?

 

[Ken1943]

I have a 500 Gb external USB disk. In W7 Ult it is recognised as a disk, given
a drive letter and works fine. In W7 Home Premium on my wife's laptop, it comes
up as a disk icon in 'Printers and Devices', has no drive letter, and apparently
cannot be read or written to. 'Properties' say it's a disk and a USB mass
storage, and is working perfectly. We want to use it as a backup device but
appear to be stymied. Any ideas about this?

Go into disk management and give it a drive letter.


KenW

 

[BillW50]

In Robin Bignall typed:

I have a 500 Gb external USB disk. In W7 Ult it is recognised as a
disk, given a drive letter and works fine. In W7 Home Premium on my
wife's laptop, it comes up as a disk icon in 'Printers and Devices',
has no drive letter, and apparently cannot be read or written to.
'Properties' say it's a disk and a USB mass storage, and is working
perfectly. We want to use it as a backup device but appear to be
stymied. Any ideas about this?

Yup, under Explorer.

Right click on My Computer
Select Manage
Select Disk Management
Select drive without drive letter
Right click.

And I think you can handle it from there. You need to assign a drive
letter basically. If that doesn't work, something else is wrong and let
us know.

 

[Robin Bignall]

In Robin Bignall typed:

Yup, under Explorer.

Right click on My Computer
Select Manage
Select Disk Management
Select drive without drive letter
Right click.

And I think you can handle it from there. You need to assign a drive
letter basically. If that doesn't work, something else is wrong and let
us know.

Thanks. I'll take a look tomorrow.

 

[Robin Bignall]

Thanks. I'll take a look tomorrow.

OK, step back a bit. This 500 Gb drive has been my external backup (NTFS) under
XP for a couple of years. Then I bought a 2T LaCie drive to replace it. When I
tried to connect them both under XP the 500 Gb vanished. They both show up
under W7U.
So, to W7HP, like in XP the drive shows up in Disk Management as "Disk 1 Unknown
Not Initialised"
I right click and try to initialise, and get an error message "Incorrect
Function" with either choice.

 

[Paul]

OK, step back a bit. This 500 Gb drive has been my external backup (NTFS) under
XP for a couple of years. Then I bought a 2T LaCie drive to replace it. When I
tried to connect them both under XP the 500 Gb vanished. They both show up
under W7U.
So, to W7HP, like in XP the drive shows up in Disk Management as "Disk 1 Unknown
Not Initialised"
I right click and try to initialise, and get an error message "Incorrect
Function" with either choice.

Do you know of some effective ways to erase disks ?

I can suggest a couple. A fast way, is as follows, but involves the command line.

1) Go to start, type "cmd" and when "cmd.exe" is shown, right-click and select
"Run as Administrator". This gives an MSDOS window, running elevated. You
need to know enough basic MSDOS commands, such as how to use "cd" to change
directories, to get to the folder you've defined holding the following download.

2) Get a copy of "dd" port from here. You will be using "dd.exe" from the ZIP.

http://www.chrysocome.net/dd
http://www.chrysocome.net/downloads/dd-0.5.zip

3) Use the command "dd --list" to get the names of all the disks.
The disks could be in the same order as in Disk Management, but that
may not be guaranteed, depending on virtual device drivers or the like.
Note that, "Partition0" is shorthand for "the whole disk", rather than
being an actual partition. "Partition1" is the first true partition. But
we're not going to be doing an operation on one partition for this. So
Partition0 is the reference needed. These are my two disks, corresponding
to Disk0 and Disk1 in Disk Management.

\\?\Device\Harddisk0\Partition0
\\?\Device\Harddisk1\Partition0

4) You use the disk size information from "dd --list", to verify you really
have the correct disk. It should be easy to tell the difference between
a 500GB and a 2TB disk.

5) Once you're absolutely sure the identity is correct, this will reset a drive.
This command will overwrite the MBR (sector 0) on Disk1 for example.

dd if=/dev/zero of=\\?\Device\Harddisk1\Partition0 bs=512 count=1

6) Now, say you have a suspicion there could still be a problem. You can also
erase a portion of the front of the disk. This would erase 100,000 sectors
or about 50MB roughly. This is erasing part of the user data area, whereas
you can recover from the command in (5) if you made a mistake. With this,
you could erase real user data.

dd if=/dev/zero of=\\?\Device\Harddisk1\Partition0 bs=512 count=100000

7) Reboot, so the OS can probe the disk again.

After that, see if you're still having a problem initializing.

If the drive is USB connected, and the drive is one of those
fancy ones with a couple partitions from the factory (one partition
containing security software), sometimes the properties of such drives
upsets Windows. If the drive is an "ordinary" drive, there really
shouldn't have been any trouble at all. You really have to be
careful if buying pre-packaged USB drives from companies like
Seagate, as the "fancy" version is the one to avoid. If you need
security, you can get that with Truecrypt instead.

Note that, on very old PCs, they do not tolerate an all-zeros MBR well. I
had one PC, that the BIOS would freeze up, when a freshly erased disk
was connected, and that was a BIOS bug. I had to initialize the disk on
another computer (a computer without that bug), then connect it, before
I could continue my work.

You can also erase areas of the disk with random data. But that isn't
necessarily going to improve system response if there is a problem. So
this is another alternative option for an "input source" when erasing.
This command would erase an entire drive, because I removed the size
limits on the command.

dd if=/dev/random of=\\?\Device\Harddisk1\Partition0

*******

The slow way is "Secure Erase". This erases the entire disk, and
could take the drive an hour or more to do.

http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml

You need to completely read the support documents, before using that.
And keep a bookmark for later, if you ever need to know what the
password was that was set. Secure Erase is a hardware command
in the ATA/ATAPI command set. SCSI drives don't have it, but
lots of IDE or SATA drives could have it, as it's been available
for a number of years. The Secure Erase program just sends that
command, and the implementation is up to the hard drive itself.
If you turn off power to the drive, while a Secure Erase is in
progress, the Secure Erase will continue on when power is re-applied,
and the disk will be unresponsive until the Secure Erase is completed.
It is better to just wait until the program tells you the command
has completed, than to turn off the power.

Paul

 

[Robin Bignall]

Do you know of some effective ways to erase disks ?

I can suggest a couple. A fast way, is as follows, but involves the command line.

1) Go to start, type "cmd" and when "cmd.exe" is shown, right-click and select
"Run as Administrator". This gives an MSDOS window, running elevated. You
need to know enough basic MSDOS commands, such as how to use "cd" tochange
directories, to get to the folder you've defined holding the following download.

2) Get a copy of "dd" port from here. You will be using "dd.exe" from the ZIP.

http://www.chrysocome.net/dd
http://www.chrysocome.net/downloads/dd-0.5.zip

3) Use the command "dd --list" to get the names of all the disks.
The disks could be in the same order as in Disk Management, but that
may not be guaranteed, depending on virtual device drivers or the like.
Note that, "Partition0" is shorthand for "the whole disk", rather than
being an actual partition. "Partition1" is the first true partition.But
we're not going to be doing an operation on one partition for this. So
Partition0 is the reference needed. These are my two disks, corresponding
to Disk0 and Disk1 in Disk Management.

\\?\Device\Harddisk0\Partition0
\\?\Device\Harddisk1\Partition0

4) You use the disk size information from "dd --list", to verify you really
have the correct disk. It should be easy to tell the difference between
a 500GB and a 2TB disk.

5) Once you're absolutely sure the identity is correct, this will reset a drive.
This command will overwrite the MBR (sector 0) on Disk1 for example.

dd if=/dev/zero of=\\?\Device\Harddisk1\Partition0 bs=512 count=1

6) Now, say you have a suspicion there could still be a problem. You canalso
erase a portion of the front of the disk. This would erase 100,000 sectors
or about 50MB roughly. This is erasing part of the user data area, whereas
you can recover from the command in (5) if you made a mistake. With this,
you could erase real user data.

dd if=/dev/zero of=\\?\Device\Harddisk1\Partition0 bs=512 count=100000

7) Reboot, so the OS can probe the disk again.

After that, see if you're still having a problem initializing.

If the drive is USB connected, and the drive is one of those
fancy ones with a couple partitions from the factory (one partition
containing security software), sometimes the properties of such drives
upsets Windows. If the drive is an "ordinary" drive, there really
shouldn't have been any trouble at all. You really have to be
careful if buying pre-packaged USB drives from companies like
Seagate, as the "fancy" version is the one to avoid. If you need
security, you can get that with Truecrypt instead.

Note that, on very old PCs, they do not tolerate an all-zeros MBR well. I
had one PC, that the BIOS would freeze up, when a freshly erased disk
was connected, and that was a BIOS bug. I had to initialize the disk on
another computer (a computer without that bug), then connect it, before
I could continue my work.

You can also erase areas of the disk with random data. But that isn't
necessarily going to improve system response if there is a problem. So
this is another alternative option for an "input source" when erasing.
This command would erase an entire drive, because I removed the size
limits on the command.

dd if=/dev/random of=\\?\Device\Harddisk1\Partition0

*******

The slow way is "Secure Erase". This erases the entire disk, and
could take the drive an hour or more to do.

http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml

You need to completely read the support documents, before using that.
And keep a bookmark for later, if you ever need to know what the
password was that was set. Secure Erase is a hardware command
in the ATA/ATAPI command set. SCSI drives don't have it, but
lots of IDE or SATA drives could have it, as it's been available
for a number of years. The Secure Erase program just sends that
command, and the implementation is up to the hard drive itself.
If you turn off power to the drive, while a Secure Erase is in
progress, the Secure Erase will continue on when power is re-applied,
and the disk will be unresponsive until the Secure Erase is completed.
It is better to just wait until the program tells you the command
has completed, than to turn off the power.

I'll have to think about that, Paul. What I don't get is that the 500 Gbdrive
works perfectly with Windows 7 Ultimate, so it must presumably be initialised
and formatted correctly. It simply isn't recognised by Windows 7 Home Premium.

 

[Paul]

I'll have to think about that, Paul. What I don't get is that the 500 Gb drive
works perfectly with Windows 7 Ultimate, so it must presumably be initialised
and formatted correctly. It simply isn't recognised by Windows 7 Home Premium.

I have other diagnostic methods, such as booting a Linux LiveCD, and use
Synaptic Package Manager to install "disktype" in RAM. Then point it at the disk,
and get an opinion. There is no Windows port of this that I know of.
But it's a great program, for getting info on storage devices (whole
drive or a partition or even a CD/DVD).

http://disktype.sourceforge.net/

To analyse the disk manually, would take a month of Sundays to explain,
and it's just easier for me to suggest erasure as the path to a solution.

For some disk problems, "Take Ownership" is the proscribed answer. But
I doubt that stops a disk from registering entirely on a computer.
For the disk to refuse to register at all, implies something fundamental
must be wrong with it. Like, maybe it's got the same disk ID as the other
disk ?

I'd probably start by dumping the MBRs of each disk, for a look. Using
that "dd" command to do it. Or, using Everest to get some info on the
storage devices and their contents. But I don't have a "recipe for
every problem" here, and there's no guarantee I could find the root cause.

Paul

 

[pjp]

OK, step back a bit. This 500 Gb drive has been my external backup (NTFS) under
XP for a couple of years. Then I bought a 2T LaCie drive to replace it. When I
tried to connect them both under XP the 500 Gb vanished. They both show up
under W7U.
So, to W7HP, like in XP the drive shows up in Disk Management as "Disk 1 Unknown
Not Initialised"
I right click and try to initialise, and get an error message "Incorrect
Function" with either choice.

Upon quick read comes to mind maybe both have been assigned same drive
letter so one isn't seen. Change the one seen's drive letter and
pwerhaps maybe the other than then also seen using the old drive letter?

Just a guess, spur of the moment when reading post.

 

[Robin Bignall]

Upon quick read comes to mind maybe both have been assigned same drive
letter so one isn't seen. Change the one seen's drive letter and
pwerhaps maybe the other than then also seen using the old drive letter?

Just a guess, spur of the moment when reading post.

Thanks, but I just discovered that W7U had fooled me, because I have so many
HDDs connected, into mistaking another drive for this 500 Gb one. In fact it
shows up in Printers and other devices on W7U, too, and is equally reluctant to
initialise. Strange, for up to a month ago it had been working perfectlyunder
XP Pro as my external backup device for a couple of years. Somehow, between
then and now it's become unusable while sitting on a shelf.

I'm too ornery to bother with technology that won't work, so it's been consigned
to the recycle bin and I've bought a new external USB drive for my wife's
laptop. Thanks to all who tried to help.

 

[Paul]

Thanks, but I just discovered that W7U had fooled me, because I have so many
HDDs connected, into mistaking another drive for this 500 Gb one. In fact it
shows up in Printers and other devices on W7U, too, and is equally reluctant to
initialise. Strange, for up to a month ago it had been working perfectly under
XP Pro as my external backup device for a couple of years. Somehow, between
then and now it's become unusable while sitting on a shelf.

I'm too ornery to bother with technology that won't work, so it's been consigned
to the recycle bin and I've bought a new external USB drive for my wife's
laptop. Thanks to all who tried to help.

The disk manufacturers have disk diagnostic tools. They can tell you whether
the disk has failed. Seatools from Seagate is an example.

Generally, a disk won't appear at all, if there is an internal failure. The
controller would have been perfectly capable of remaining in communication
at all times, if they'd designed it that way. But instead, ATA disks "disappear"
when no longer functional. And a disk diagnostic cannot resurrect a dead drive,
if the interface on the ribbon cable or SATA cable no longer works.

Some particular drive models, have known firmware issues. Which is why,
I would recommend Googling the model number as your first step.

If there are no outstanding firmware related issues, then you could spend
a few minutes running Seatools from Seagate (windows or MSDOS version)
as a test tool. And that will tell you whether it's gone or not. Western
Digital will have a diagnostic on their site as well.

The reason they offer diagnostics, is as an aid to warranty claims.
If there is an error code coming from the diagnostic, it makes
it clearer to the manufacturer that a warranty claim is needed.

Paul

 

[Robin Bignall]

The disk manufacturers have disk diagnostic tools. They can tell you whether
the disk has failed. Seatools from Seagate is an example.

Generally, a disk won't appear at all, if there is an internal failure. The
controller would have been perfectly capable of remaining in communication
at all times, if they'd designed it that way. But instead, ATA disks "disappear"
when no longer functional. And a disk diagnostic cannot resurrect a deaddrive,
if the interface on the ribbon cable or SATA cable no longer works.

Some particular drive models, have known firmware issues. Which is why,
I would recommend Googling the model number as your first step.

If there are no outstanding firmware related issues, then you could spend
a few minutes running Seatools from Seagate (windows or MSDOS version)
as a test tool. And that will tell you whether it's gone or not. Western
Digital will have a diagnostic on their site as well.

The reason they offer diagnostics, is as an aid to warranty claims.
If there is an error code coming from the diagnostic, it makes
it clearer to the manufacturer that a warranty claim is needed.

Thanks, Paul, but it isn't worth it. The drive itself is an IDE in a USB
enclosure designed for IDEs. It was the system disk for the PC I built when I
first went from W98 to XP, so it's quite old and I'm not surprised it's gone
wonky.
The disk I've bought her matches her laptop and mouse (not black or silver).