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USB 2.0 Hard drive - Lost Connections

Posted on 2006-04-28
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Last Modified: 2012-05-05
I have a MHV2080AT 2.5" notebook drive in a Bytecc 2.5" HDD USB 2.0 Mobile External Enclosure.  I have several of these units installed as backup drives at several different clinet locations.  I have logged several instances of these drives becoming invisible to Windows XP.  At first I thought that there was marginal USB poret power, but that is clearly not the case since I have observed this "disappearnce" on drives running off of a powered USB 2.0 hub as well.  They are running on 3 and 6 ft USB 2.0 cables.

1) What is cuasing this?

2) How do I prevent this from happening?

Since I rely on thes drives for data backup - it is very undesireable for these drives to disappear as this causes the backups to fail.
I am running these drives on Dell Optiplex and Precision Workstations.

Thanks for any information which can help me get to the root of this mysterious phenomenon.

Bill
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Question by:billrush2
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by:garycase
ID: 16567315
Are these computers used with other USB devices -- notably USB flash drives?   I've seen many cases where a "Safely Remove" was done on the wrong drive letter -- if that's been done here, then the drives are functionally disconnected until they are unplugged and then re-inserted.

Another thing that can cause this is a drive letter conflict.   Did you assign an out-of-the way drive letter for these drives (T, S, U, V, etc.) that's not likely to ever conflict with any other "transient" assignments?  (cameras, flash drives, etc.)



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by:tmj883
ID: 16567581
You should explore the possibility of bad capacitors on your mainboards. We are in the process of replacing approx 30 mainboards on our Dell Optiplex workstations GX240/270. Fortunately we have a parts contract but we're stuck with the labor(only 20-30 minutes to replace though). The only symptom has been unpredictable errors while remaining basically functional. We have not had outright failures, just problems similar to your's.
http://www.badcaps.net/
No slam on Dell as they have been great about the issue.
Note: physical examination has not revealed any leaking or buldging of the capacitors, so they can still be bad and not show physical damage.
T
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by:nobus
ID: 16567907
i have seen a lot of posts on this topic, and usually it is caused by upgrading.
The only real solution i know to work is a complete install.
Other things have been suggested, and said to work in some cases, but did not work in all cases, like deleting all USB entries from device manager, and reboot.
In many cases, the drives can still be accessed from disk management, but cannot be seen in explorer
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by:motaz_mohamed
ID: 16568292
I believe this could be one of two:
1. Power saving options that might be turning off some of your devices. This can be disabled from the PC's setup.
2. USB communication problems. Installing SP2 should solve this.
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Author Comment

by:billrush2
ID: 16568442
garycase

I typically assign H or I to these drives.  So they are out there a little, but it seems like a good idea just to start at the opposite end of the alphabet just to get this issue out of the way completely, if it is a factor.

As far as USB Flash drive usage, I do not think this is a factor just based on the usage of these PC's.

Bill
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Author Comment

by:billrush2
ID: 16568447
tmj833

is there a definitive test to determine whether this migh be the case?  Also, is there a workaround such as using a powered USB hub?  Maybe a powered hub would render the bad cap MB issue moot since the power output of the USB would not be what we are relying on.  Does any of this sound sensible?

Bill
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by:tmj883
ID: 16568725
No test as the problems generated with this issue are random errors. Replacement was prompted by Dell. A powered hub may eliminate power issues as a cause, but is not a solution for bad caps if this is the issue.
T
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garycase earned 750 total points
ID: 16568965
It's been some time since I used Devcon, but you could schedule a simple batch file that used Devcon to install the USB drive if it's been disconnected.  (http://technet2.microsoft.com/WindowsServer/en/Library/2df5cad6-e244-4db7-97a0-b42ad935377b1033.mspx)

Keep a simple flag file on the hard drive ("DrivesOkay.txt" or some such) and use something like:

If Exist T:DrivesOkay.txt goto USB_Drive_Ok
Devcon rescan
USB_Drive_Ok

Note:  I'm not SURE the rescan will reconnect USB devices;  you may need to be more specific and use Devcon install <instanceID>.   This can be a bit tricky to get right ==> and as I noted, it's been a few years since I used it.   But once it's set up, it should be a very reliable way to check for the drive, and then simply reconnect it if it's missing.   Doesn't solve the "why it's happening" issue; but will make sure it's there when your backup program/script needs it.
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by:Visual3DMaya
ID: 16576408
I had a similar issue to my enclosure and fortunately found the cause and now am very happy, had no disconnection by then. The adaptor internal power connector, like a floppy unit connector, was so syphilitic so it didn't keep tight and didn't make all the time electrical contact. So i pulled out half of it to stay fixed.
Try the same and let me know...
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by:FriarTuk
ID: 16593928
Open (device manager) devmgmt.msc, expand usb cntlrs, check the properties of each usb hub root ( on the Power tab) to find your usb device, then try unchecking the "allow pc to turn off dev to sav pwr" on the Power Mgmt tab.
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by:nobus
ID: 16593986
you can try this :

open regedit, navigate to :
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
then delete All of the \DosDevices\ ... values correspond to external usb drives/keys/thumbdrives etc

reboot and test
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Author Comment

by:billrush2
ID: 16595076
FriarTuk,

I have previously tried this and have been watcvhing to see if this fixes the issue.

Thx
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Author Comment

by:billrush2
ID: 16595088
nobus,

Can you give me some understanding on this.  What is this reg mod actually doing.  I am a little hesitant to make reg edits
without a good understanding what is being done and possible side effects.

Thanks,
Bill
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by:nobus
ID: 16595317
it does what it says: it removes all installed usb devices.
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Author Comment

by:billrush2
ID: 16595355
nobus,

Please explain - "removes all installed usb devices"?  Forever? Are these reinstalled on reboot.  The drives I am having issues with are USB devices.  

Bill
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by:nobus
ID: 16595536
>>   Are these reinstalled on reboot   <<   Yes, that is the whole idea. xp registers each usb device, so, if you have problems with registering this happens. If you are unsure, ask some other tech do it for you
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Author Comment

by:billrush2
ID: 16595622
nobus

Thanks

Bill
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by:nobus
ID: 16596016
No problem - have PC fun !
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by:FriarTuk
ID: 16688959
hey bill, what's the status?
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Author Comment

by:billrush2
ID: 16689273
Still do not have clear resolution - most recent case was remedied by simple device disconnect and reconnect.  While that sometimes works, I would like to knowwhat is causing this and how to prevent it from happening the first time.  Fundamentally why is this USB connection so "fragile"?

Bill
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by:nobus
ID: 16689359
i told you what causes it. you can do not much to prevent it
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by:billrush2
ID: 16689432
nobus,

I believe you said (earlier post) that the problem was due to "upgrading" and that reinstall was only way to fix it.  What upgrasde is causing this?  This is happening on OEM XP (SP2) boxes where no "upgrades" have occurrred , unless you are referring to a particular XP hot fix.  It would be very helpful if you could provide details of what you mean by upgrading. Upgrading can mean a lot of different things.  Can you give me a MS tech article on this?

Thx,

Bill
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by:nobus
ID: 16689749
i did not say that : i said :"xp registers each usb device, so, if you have problems with registering this happens" and of course, it can be caused by upgrading, but i do not say it is the only reason.
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Author Comment

by:billrush2
ID: 16689809
nobus,

maybe I misunderstood - from your 4/29/06 post responding to my question of what causes the problem (so i can prevent it)

"i have seen a lot of posts on this topic, and usually it is caused by upgrading.
The only real solution i know to work is a complete install."

This is what I was referring to regarding what "upgrading" means

Bill
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by:nobus
ID: 16690735
oh - i see; it refers to upgrading XP. But remember it is not the only cause.
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by:billrush2
ID: 16690759
OK - thanks
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by:FriarTuk
ID: 16696044
hey bill, did you already uncheck the power scheme option to not turn off hard disks?

when this occurs, is your pc entering/in/exiting either standby or hibernate?

when this occurs have you checked your eventlogs for any errors within 30 minutes?
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Author Comment

by:billrush2
ID: 16698915
FriarTuk,

USB Root Hubs and Windows power Scheme both have been set to prevent powering off hard disks

There is no hibernate option in this PC's power options panel??  I have never seen this

Checked event logs and cannot find anything that relates to the missing USB drive.

This PC does have a large number of USB connected devices in the USB connctions panel at the back of this PC - maybe I should try a powered USB hub to feed this drive?

I am going to reestablish this connection by unplugging it and replugging.  After that I am going to watch the event log to see if I can focus in on this more.

Any other ideas?
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by:nobus
ID: 16699346
>>   maybe I should try a powered USB hub to feed this drive?   <<  that is always a good idea
 >>  There is no hibernate option in this PC's power options panel??    <<   maybe your OS is n't correct anymore; try running sfc /scannow from the run box
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Author Comment

by:billrush2
ID: 16717944
nobus,

I finally was able to access the problem PC and grab a snapshot of the "mounted devices" from the registry.  Please take a look at:

http://www.rushtech.net/EDA_mounted_devices.JPG

Does this confirm your suspicions?  Also deleting all dos devices looks like it will remove more than just the USB drives, keys, thumb drives, etc.  Comment?

Thx,

Bill
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by:nobus
ID: 16718736
please read my post again - it explicitly says : delete ALL keys related to USB devices
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by:nobus
ID: 16718750
and if you are not sure, make a registry backup first, or set a restore point
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Author Comment

by:billrush2
ID: 16718803
nobus,

I believe it says "delete All of the \DosDevices\".  My question is simply to clarify that you really mean all keys in |\DosDevices\ as it looks to me to contain non USB drives as well as the USB drives.

Please clarify your answer - this will help my understanding.

Thanks,

Bill
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by:nobus
ID: 16718886
here the complete post : Date: 05/03/2006 12:50AM PDT

you can try this :

open regedit, navigate to :
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
then delete All of the \DosDevices\ ... values correspond to external usb drives/keys/thumbdrives etc

reboot and test
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Author Comment

by:billrush2
ID: 16718969
nobus,

I read your post - you are not answering my question.  You posted instructions are unclear as to which keys to delete.  I understand that I can backup the reg and just delete everything whether it relates to USB or not and see what happens.  If you are unwilling or unable to clarify this, then that is OK.  I do not wish to play games.

Bill
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by:nobus
ID: 16719513
me neither.
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by:garycase
ID: 16719592
Bill -- deleting the DosDevices keys will delete all of the associations of drive letters with those devices, whether they're USB-attached or not.   The devices will be redetected on the next boot (or insertion in the case of a USB device); and you can re-assign the drive letters as appropriate.
To do what nobus is suggesting, you would only delete those DosDevices associated with a USB device (e.g. I presume "Z" is the device in question here).    I think this is unlikely to help with your issue;  but it won't hurt to try it.

Did you try the simple Devcon batch file I suggested?   Something like this:  (you need to have a file on the external drive names "DrivesOkay.txt" for this to work.

If Exist T:DrivesOkay.txt goto USB_Drive_Ok
Devcon rescan
:USB_Drive_Ok

As I noted before, the "rescan" may not be enough -- you MAY have to use

Devcon install <instanceID>

instead of the simple rescan command.   In this case it's important to get the correct <instanceID>; which you could get with Devcon while the drive is connected and working.
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Author Comment

by:billrush2
ID: 16721001
garycase,

First, thanks for answering my question regarding the registry stuff.  I have not been able to try the Devcon suggestion as I cannot get the device to be recognized by the PC at all right now, so I cannot get the instance ID.  Does devcon rescan do the same thing that a rescan from device manager does.  If so, this is not enough to get the device back.  On one prior occasion, I have been able to get the device back by disconnecting the USB connector and then reconnecting it - that is not doing the trick at the moment.

Once I get the instance ID, can I simply replace the line in your script  "devcon rescan" with "devcon install <instance ID>?

Thank for your help,

Bill

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by:garycase
ID: 16721951
Yes, the "devcon install <instanceID>" should force an install.   You do, however, have to know the instanceID for that to work -- and without the device installed that's difficult !!

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by:FriarTuk
ID: 16723696
try deleting both of these keys (from left pane window in regedit), & during reboot it will redetect & reinstall usb devices

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USBSTOR

also delete from:                          controlset001
                                                   controlset002
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Author Comment

by:billrush2
ID: 16724349
FriarTuk

Just experimenting a little with devcon on my workstation (eventhough I currently have no instance ID from my client's problem PC).  When I create and run a batch ffile with any of the devcon list commands, all I get is an endless loop (dos window with the command repeating over and over).  This is true for "devcon hwids *" and most other devcon list cmds I have tried from the link you gave me in an earlier post.  I must be doing something wrong in terms of syntax?

I will try the regedit, but not at this time since I do not want to do the regedit remotely.  If I run into a problem, my dental client will be out of business for the day.  They are located 2 hrs away.

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Author Comment

by:billrush2
ID: 16724411
FriarTuk,

OK - got devcon to run - please ignore prvious post -  yes this is a very useful and powerful tool!
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Author Comment

by:billrush2
ID: 16724540
OK - closing in on this a little bit.  After studying devcon for a while now, I do not see a way to find the "instance ID".  I can find hardware ID's, but I do not know how to find the instance ID.  Not sure even what the instance ID looks like.  If I can nail this down, I can then do a batch file to force the install as needed in the future.



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by:garycase
ID: 16724945
devcon hwids *

... will show all of your current ID's.

I suspect you've done this ("... I can find hardware ID's ...") ==> and as you've noted there are multiple instance ID's for a device.   Only one matters -- and that's the tricky part of using Devcon.   Been a couple years since I need/used it -- as I recall I experimented with the different ID's listed for the device I was messing with (a USB memory card reader IIRC) until I found the ID that worked with the "install" command.   Then it was just a simple "devcon install <instanceID>" to force the reader to re-install.   I no longer have that reader -- my current memory card reader is on a network printer, so I don't have the uninstall issue anymore.

The "RenewUSB" script on this page may be useful for you -- and even if not this guy's done a lot of work with Devcon that you may find interesting/useful:
http://www.robvanderwoude.com/index.html
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Author Comment

by:billrush2
ID: 16725309
garycase,

So to be clear, are the multiple lines associated with each device shown in the results of the hwids* instance ID's?  Here is the result of hwids *usb* with one of these little laptop drives (same device type I ham problems with on a client's PC) hooked up to my workstation:
USBSTOR\DISK&VEN_FUJITSU&PROD_MHT2080AT&REV_0811\8&29C5C193&0
    Name: FUJITSU MHT2080AT USB Device
    Hardware ID's:
        USBSTOR\DiskFUJITSU_MHT2080AT_______0811
        USBSTOR\DiskFUJITSU_MHT2080AT_______
        USBSTOR\DiskFUJITSU_
        USBSTOR\FUJITSU_MHT2080AT_______0
        FUJITSU_MHT2080AT_______0
        USBSTOR\GenDisk
        GenDisk
    Compatible ID's:
        USBSTOR\Disk
        USBSTOR\RAW

So if I understand, there are 6 instance ID's for this device?

Bill
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by:garycase
ID: 16725567
Yes -- and I simply don't remember how I determined which one to use with the Install command.  (probably through experiementation)
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by:garycase
ID: 16725575
... Did you try the RenewUSB script ?
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Author Comment

by:billrush2
ID: 16725848
Not on my client's PC but I did run it on my workstation.  I just need to be on site if something does not reinstall or if I need a driver off of a CD in the office, etc.  Thanks for the link, he has a number of great scripts for devcon.

I tried some devcon installs on my PC and could not determine what was successful and what was not.  The DOS screen just flashed.  Of course I was doing an install on a device that is already running - not sure what diff that makes.

Bill
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by:garycase
ID: 16725873
... Devcon is a great little tool -- but very poorly documented (as you can tell).   It's one of those things that I once used -- and it did the job perfectly -- but haven't used for a long time and don't remember the details.   Hopefully the simple RenewUSB script will resolve your issue.

If not, you need to experiment to find the correct ID; and then use something like this (where "DriveIsOkay.txt" is a dummy file located on the external drive):

If Exist T:DriveIsOkay.txt goto USB_Drive_Ok
Devcon Install  <DeviceID>
:USB_Drive_Ok

To test, I DO think the device needs to NOT be currently running -- otherwise you don't know if the install worked or not.   You could also add a few comments and pauses to the script so you'd know it was getting read to try the install and whether or not it was successful -- e.g.

If Exist T:DriveIsOkay.txt goto USB_Drive_Ok
Echo Ready to Install Device
Pause
Devcon Install  <DeviceID>
If Exist T:DriveIsOkay.txt goto USB_Drive_Installed
Echo Drive NOT Installed
Pause
goto Done
:USB_Drive_Installed
Echo Drive Successfully Installed
Pause
goto Done
:USB_Drive_Ok
:Done
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Author Comment

by:billrush2
ID: 16728143
garycase,

Is there any chance that the Instance ID's will be the same for my client's PC as the ones gererated on my PC - I am using the exact make and model of external drive?  This would help a lot.  Otherwise, on my clinet's PC, if I get the drive to show and I run hwids*usb*, will the instance ID's always be the same for a given host PC and a given external drive?

Bill
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by:garycase
ID: 16729101
I don't know the answer to your first question -- but the answer to the 2nd is Yes, for a given host PC and given external drive the Instance ID's will always be the same.
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by:FriarTuk
ID: 16730506
more on devcon here:  http://support.microsoft.com/kb/311272/

also removing all usb from registry, then rebooting, will force xp to reinstall needed drivers for detected devices.
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Author Comment

by:billrush2
ID: 16730892
FriarTuk,

Have not forgotten about your suggestion - just won't be on site for a while.  Devcon is a preferred solution if it works simply due to the fact that it looks as though a script w/ devcon commands may be able to periodically detect and repair any issues that arise.  This is preferred due to the automated nature.
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by:FriarTuk
ID: 16885811
hey bill, any more updates for us?
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by:garycase
ID: 16885867
You might also try this -- it's a service and may provide better stability:
http://www.uwe-sieber.de/usbdlm_e.html
(it also provides a lot of options in terms of setting the drive letters, etc.)
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Author Comment

by:billrush2
ID: 16946492
Update - I found the problem with one of these drives to be a bad circuit board in the drive enclosure.  I replaced the drive and now the drive is not "disappearing".  I still have one last problem PC.  I will replace the drive and see if I still have the problem.  A lot of possiblities have been posted wrt the cuase and possible solutions.  I just do not want to try to fix what may be a bad drive (defective enclosure circuit) with a software band aid.  

I apologize that this is taking so long.

Bill
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Author Comment

by:billrush2
ID: 16968045
OK - I just replaced the external USB drive with a new one which has tested out OK.  I also have captured the device ID so if the drive disappears, I will try Devcon to see if that can re-establish the presence of the invisible drive.

Bill
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by:garycase
ID: 16969941
... sounds good -- keep us posted :-)
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Author Comment

by:billrush2
ID: 17036756
OK - Devcon Install appears to do the trick however when I run the script, the install command goes into an endless loop and I have to close the DOS window manually.  The script that is behaving this way is:


If Exist F:DriveIsOkay.txt goto USB_Drive_Ok
Echo Ready to Install Device
Pause
Devcon Install  USB\VID_05E3&PID_0702\5&13069516&0&4
If Exist F:DriveIsOkay.txt goto USB_Drive_Installed
Echo Drive NOT Installed
Pause
goto Done
:USB_Drive_Installed
Echo Drive Successfully Installed
Pause
goto Done
:USB_Drive_Ok
:Done

The logic of this script seems fine - is there a syntav error?  I am running this as a .bat file.

Bill
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by:garycase
ID: 17037390
Okay than the fact that your "goto Done" command just before the label ":USB_Drive_Ok" is extraneous (the code would fall through fine without it) the script is fine -- there's no path back to the beginning.   You might add an "Exit" command at the end -- I do for completeness sake in my scripts; but when the end is encountered that's supposed to be done automatically.

Is the "Drive Successfully Installed" message being echoed??

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Author Comment

by:billrush2
ID: 17037594
garycase,

I added the exit command but no change - the dos window still just endlessly loops the devcon install command.  

The echo is also not happening.

Bill
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Expert Comment

by:garycase
ID: 17038256
The Devcon command must not be completing -- your script is fine !!

What happens if you manually execute the exact same Devcon command in a command window?

... also, you might see if the behavior varies between CMD and COMMAND  (is your batch file a .BAT file or a .CMD file ??)
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Author Comment

by:billrush2
ID: 17038406
Using .bat file.  Same behavior using a manually typed command.

Bill
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Author Comment

by:billrush2
ID: 17038409
I also tried using a .cmd extension - same result.

Bill
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by:garycase
ID: 17038449
... The syntax looks correct for Devcon -- I'm not sure why it's not completing the command.

Since you get the same behavior if you manually type it, it's clearly a DEVCON syntax issue.   You simply need to resolve that and the script will work fine ...

I'll look through the DEVCON documentation and see if anything "clicks" ...
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Author Comment

by:billrush2
ID: 17038470
Thanks!
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