Re-mount a USB drive that I've unmounted?

[Bert Hyman]

Windows XP Pro SP3

I have a USB-connected external hard drive.

If I've unmounted it via the "Safely Remove Hardware" procedure, is there
any way to re-mount it without either unplugging it and plugging it back in
again or turning it off and then back on?

 

[Bob Lucas]

You could try Control Panel / Add Hardware - and let the wizard
search for the "new" hardware.

However, I suspect the wizard will find the USB external hard
drive - and produce an error message, warning you that it cannot
install the device, because it has been prepared for removal.

If so, you may have no alternative but to unplug it - or turn it
off and on again. Is that a problem?

 

[Bert Hyman]

In "Bob Lucas"

You could try Control Panel / Add Hardware - and let the wizard
search for the "new" hardware.

Using the Device Manager's "Scan for hardware changes", which should
be the same operation, does nothing.

...

If so, you may have no alternative but to unplug it - or turn it
off and on again. Is that a problem?

Well yes; that's why I asked

Sometimes, I'm not sitting at the PC when I realize I need to do this.

 

[turbo]

You could try Control Panel / Add Hardware - and let the wizard

Using the Device Manager's "Scan for hardware changes", which should
be the same operation, does nothing.


Well yes; that's why I asked

Sometimes, I'm not sitting at the PC when I realize I need to do this.

Try Windows Explorer- My Computer single click-- then F5

 

[Bert Hyman]

In "turbo"

Try Windows Explorer- My Computer single click-- then F5

Nothing happens; what did you expect to happen?

 

[John John - MVP]

Windows XP Pro SP3

I have a USB-connected external hard drive.

If I've unmounted it via the "Safely Remove Hardware" procedure, is there
any way to re-mount it without either unplugging it and plugging it back in
again or turning it off and then back on?

As far as I know the only way of doing this is to use the Devcon utility
to remove USB\ROOT_HUB where the drive is connected and then use the
same utility again to rescan for new hardware, Devcon will find the hub
and restart the attached device. Be warned that if you make mistakes
with Devcon things can get *very* messy in a hurry! Make a System
Restore point before you start experimenting with this.

Basically you will have to use the Device Manager to find the USB Root
Hub where the drive is attached (it will be easier to find if you set
the View option to show Devices by connections) and then you remove the
hub with thr Devcon utility and rescan, it's all explained here:
http://www.dti.nu/usb/

The Devcon utility is available here:
http://support.microsoft.com/kb/311272

You will find some who suggest that you remove all the USB Hubs with the
"devcon remove @usb\*" command and then rescan, I strongly advise
against doing this, especially if you have other devices on other USB
ports! Also keep in mind that if you plug the drive in a different hub
that you will have to verify and make sure that you remove the right hub
the next time you run the command, if you make a batch file to automate
this procedure you have to make sure that you always plug the drive in
the same hub.

John

 

[Bert Hyman]

In John John - MVP

As far as I know the only way of doing this is to use the Devcon
utility to remove USB\ROOT_HUB where the drive is connected and then
use the same utility again to rescan for new hardware, Devcon will
find the hub and restart the attached device. Be warned that if you
make mistakes with Devcon things can get *very* messy in a hurry!
Make a System Restore point before you start experimenting with this.

Thanks!

Overkill for what I thought was a simple problem, but the docs suggest that
it will do just what I want.

The fact that it has a command-line interface answers the other question
that was lurking in the back of my mind

 

[John John - MVP]

In John John - MVP


Thanks!

You're welcome. You might also find some useful information on Uwe
Sieber's web site, he's an expert on USB drives. Uwe suggests that you
can use Devcon to deactivate the device rather than using the "Safely
remove hardware", this might be less messy than removing the root hub.

Reactivate a USB drive

When a drive has been prepared for safe removal then it can be
reactivated only by replugging it. Alternatively the device could be
deactivated and later reactivated instead being prepared for save
removal. This can be done by means of Microsoft's command line tool
DEVCON like this:

devcon disable USB\VID_067B*PID_2517*
devcon enable USB\VID_067B*PID_2517*

[end quote]

http://www.uwe-sieber.de/usbstick_e.html

As a matter of fact, after reading the information on his site I may
have found out why I couldn't simply remove the drive instead of the hub
and then rescan to see if it would restart the drive. I was trying to
remove the drive with something like this because the ampersand in the
hardware ID was causing expected problems:

devcon remove USB\VID_067B*

But this was failing, it couldn't remove the drive, so I moved up to the
hub root to get around the problem.

Uwe says: "The & has a special meaning on the XP command line, so
replacing it by * (placeholder for any characters) is an easy way to
prevent problems."

Uwe's suggestion to use something like this might work to remove the
drive instead of the hub:

devcon remove USB\VID_067B*PID_2517*

I'll try it latter and see if it works.

John

 

[John John - MVP]

this might work to remove the drive instead of the hub:

devcon remove USB\VID_067B*PID_2517*

I'll try it latter and see if it works.

Doesn't work, once the drive has been prepared for removal Devcon no
longer sees it. You have to remove the hub.

John

 

[Richard]

Windows XP Pro SP3

I have a USB-connected external hard drive.

If I've unmounted it via the "Safely Remove Hardware" procedure, is there
any way to re-mount it without either unplugging it and plugging it back
in
again or turning it off and then back on?

In "Bob Lucas"


:

Using the Device Manager's "Scan for hardware changes", which should
be the same operation, does nothing.


:

Well yes; that's why I asked

Sometimes, I'm not sitting at the PC when I realize I need to do this.

Hi Bert,

I'm puzzled why you are using the Safely Remove option if you do not want to
remove it... to flush any Delayed Write data to the drive so you can switch
it off? Why not change the policy tab of the device to "Optimize for safe
removal", so there is no need to use the Safely Remove Hardware option?

Have you queried the Command Prompt "rsm" (Removable Storage) command, to
see if that is something you could use?

C:\>rsm mount /?
C:\>rsm dismount /?

FWIW. --Richard

 

[Bert Hyman]

In "Richard"

I'm puzzled why you are using the Safely Remove option if you do not
want to remove it...

Because sometimes my fingers move faster than my brain.

to flush any Delayed Write data to the drive so you can switch it off?
Why not change the policy tab of the device to "Optimize for safe
removal", so there is no need to use the Safely Remove Hardware
option?

I thought about that, but the description of the option says that it
disables caching in the drive as well as Windows' own caching, and I'm
just assuming that the performance hit would be significant.

Maybe I ought to try it that way for a while and see if it really
matters.

Have you queried the Command Prompt "rsm" (Removable Storage) command,
to see if that is something you could use?

First I've heard of it; I'll look into it to see what it does.

 

[Uwe Sieber]

As far as I know the only way of doing this is to use the Devcon utility
to remove USB\ROOT_HUB where the drive is connected and then use the
same utility again to rescan for new hardware, Devcon will find the hub
and restart the attached device.

disable and then enable the hub where the device in
question is attached to is enough. It does not
matter if it is a root hub or a usual hub.

So, putting a hub before the device in question,
restarting the this hub will wake up the device
without restarting other devices.


Uwe

 

[Twayne]

disable and then enable the hub where the device in
question is attached to is enough. It does not
matter if it is a root hub or a usual hub.

So, putting a hub before the device in question,
restarting the this hub will wake up the device
without restarting other devices.


Uwe

May I be so bold as to ask why you don't want to simply power-cycle the
external drive? I'ts not in use so there won't be any downside to it.

Just curious. No problem if you don't wish to respond.

Regards,

Twayne`

 

[Bert Hyman]

In "Twayne"

May I be so bold as to ask why you don't want to simply power-cycle
the external drive? I'ts not in use so there won't be any downside to
it.

I started this thread because I often access my system remotely and have
occasionally "removed" the drive without thinking.

Getting it back requires that I trudge downstairs and power cycle the
drive, and I was just looking for a way to get it back without doing
that.

 

[Bert Hyman]

In jetjock

Bert,

Here is a link to a small program that I had the folks who built my
computer install for me.
...

You seem to have forgotten the link

But, if the "Scan for hardware changes" that it performs is the same as
what the Device Manager does, it won't find a USB-connected drive.