WinUSB coinstaller problem on 64-bit machines

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Paarvai Naai

May 30, 2008, 12:01:01 PM5/30/08
I've constructed an INF file as described in the WinUSB "How to"
document and things work nicely on 32-bit versions of XP and on Vista
(32-bit and 64-bit).

However, while installing the driver on 64-bit machines I noticed that
the 64-bit WinUSB co-installer was not updating the 32-bit winusb.dll
in SysWow64. To test this, I manually removed winusb.dll from
SysWow64 and ran the installer. The 64-bit co-installer did not
replace this missing DLL as I would have expected. The 64-bit DLL was
correctly installed in System32.

My concern is that if there are updates to winusb.dll in the future,
the co-installer should replace both the 32-bit and 64-bit versions of
winusb.dll. It looks like it's not currently doing that.

Is there something that needs to be specified in the INF file to cause
the co-installer to install the 32-bit DLL in SysWow64?

Paarvai Naai

Jun 23, 2008, 8:37:00 PM6/23/08
Has anyone else experienced this issue?

Here are the steps to reproduce:

1) Use a 64-bit Vista machine that has the default WinUSB installed
2) Delete System32\winusb.dll and SysWow64\winusb.dll
3) Use an INF file that references the WinUSB co-installer
4) Install a device that invokes this INF file

System32\winusb.dll is restored, but SysWow64\winusb.dll is not.

This suggests that SysWow64\winusb.dll will not be installed or upgraded by
the coinstaller.

Any help would be most appreciated.


Jun 23, 2008, 11:04:26 PM6/23/08
On Jun 23, 7:37 pm, Paarvai Naai
<> wrote:

> System32\winusb.dll is restored, but SysWow64\winusb.dll is not.
> This suggests that SysWow64\winusb.dll will not be installed or upgraded by
> the coinstaller.

Does it work on Linux and Darwin?

Doron Holan [MSFT]

Jun 24, 2008, 1:12:00 PM6/24/08
since vista ships with winusb, the winusb coinstaller does nothing on the
OS. you are deleting an OS file and expecting it to magically
reappear...that will not happen


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"Paarvai Naai" <> wrote in message


Jul 3, 2008, 4:27:01 AM7/3/08
I am also facing the same problem.

When installing the driver into WinXP(x64), the co-installer does not locate
the 32bit version of WinUsb.DLL at SysWow64, thereby 32bit processes using
WinUsb.DLL do not work at all. However, WinXP(x64) does not come with 32bit
WinUsb.DLL at SysWow64 as default, so who can copy the DLL into SysWow64?

I upgraded the OS with using "Windows Server 2003 (x64) SP2", but nothing

What I tried is co-installer VER1.5. Did anybody try VER1.7 co-installer?

Paarvai Naai

Jul 8, 2008, 3:10:22 PM7/8/08
Hi Doran,

Thanks for your reply. You are correct that deleting system files in
Vista is not be advisable. This was just a toy example and we can
instead look to Win XP for more evidence regarding this issue.

Similar to the experience of manik_66, we too found that using the
WinUSB coinstaller on Windows XP 64-bit did not result in the
SYSWOW64/winusb.dll (32-bit version) being installed. Only the
SYSTEM32/winusb.dll (64-bit version) is installed.

After copying the SYSTEM32/winusb.dll (32-bit version) from an XP
32-bit machine to the XP 64-bit machine, my 32-bit application ran
without incident on the 64-bit OS.

Please note that I had also posted previously regarding whether WinUSB
is supported on XP 64-bit at all:

Finally, my understanding was that, while Vista ships with WinUSB
pre-installed, the coinstaller mechanism allows a way to update WinUSB
if a new version is subsequently released. The information above
highly suggests that the coinstaller may not properly update the

Can you please shed some light on this?

Best regards,

Paarvai Naai

Jul 8, 2008, 3:13:12 PM7/8/08
Hi manik_66,

Yes, this is exactly what I saw.

I tried version 1.7 of the *WDF* co-installer. However, this
does not make a difference since it is the *WinUSB* co-installer that
is responsible for installing the winusb.dll. As far as I know,
there is only one version of the WinUSB co-installer currently

Best regards,

Paarvai Naai

Jul 16, 2008, 3:25:02 PM7/16/08
Hi all,

Is there anyone who can provide input on this Windows XP 64
coinstaller issue or Windows XP 64 compatibility issue for WinUSB?

To summarize my previous email quoted below, the documentation does
not list Windows XP 64 as a supported OS for WinUSB. However it seems
to work, except for the fact that the coinstaller does not install
the SYSWOW64/winusb.dll. It appears manik_66 has seen the same
behavior as me.


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