How to use Wix Toolset to install a device driver from it's driver package files?

[meedinst]

Hi all! I am having some issues using WiX v3 and DifX. This thread is the same as my post to stackoverflow here.

I have created a .wixproj installer for my WPF program which successfully installs my WPF application. I now want to add the installation of a device driver as part of this installation as this device is required for using certain parts of the WPF app. However, having included the driver files in their own component and using the DIFX Driver tag, the installer project can be built but the installation fails when it gets to the DIFX component.

I have one file, Drivers.wxs, where I create the components and use the DIFXAPP Driver tag:

<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns=http://schemas.microsoft.com/wix/2006/wi
       xmlns:difx=http://schemas.microsoft.com/wix/DifxAppExtension>
       <Fragment>
              
              <ComponentGroup Id="Drivers">
                     <ComponentRef Id="cyusb"/>
              </ComponentGroup>

              <DirectoryRef Id="INSTALLFOLDER" FileSource="..\Installer\drivers">

                     <Directory Id='DriverFolder' Name='Drivers'>

                           <Directory Id='CYUSBFolder' Name='CyUSB'>

                                  <Component Id="cyusb" Guid="{6125BDA1-74B9-443C-B130-494C60367EA4}">
                                         <File Id="cyusb.sys" Name="CyUSBsys" Vital="yes" Source=".\drivers\cyusb\cyusb3.sys" KeyPath="yes" />
                                         <File Id="cyusb.cat" Name="CyUSBcat" Vital="yes" Source=".\drivers\cyusb\cy_devices.cat" />
                                         <File Id="cyusb.inf" Name="CyUSBinf" Vital="yes" Source=".\drivers\cyusb\Cy_Devices.inf" />
                                         <difx:Driver Legacy="yes"/>
                                  </Component>
                                  
                           </Directory>

                     </Directory>

              </DirectoryRef>
              
       </Fragment>
</Wix>

Then I reference this component group in my Product.wxs within the product tag alongside all my other features:

<!--Define components, shortcuts, files etc for installer-->
    <Feature Id="ProductFeature" Title="AnalytacleClientInstaller" Level="1">

        <ComponentGroupRef Id="Drivers"/>

        <ComponentGroupRef Id="ProductComponents" />
        <ComponentGroupRef Id="CompiledComponents"/>
        <ComponentGroupRef Id="FileTypeComponents"/>
    </Feature>

I have also added the DifxAppExtension as a reference for my project and added the Difx library reference within the .wixProj file itself :

<WixLibrary Include="difxapp_x64.wixlib">
  <HintPath>difxapp_x64.wixlib</HintPath>
  <Name>difxapp_x64.wixlib</Name>
</WixLibrary>

There are no errors or warnings and I am able to build my installer just fine, but when I run the install it fails with the same error message each time, here is a snippet from the log where DIFXAPP starts:

DIFXAPP: ENTER: InstallDriverPackages()
DIFXAPP: INFO: 'CustomActionData' property 'DIFxApp Version' is '2.1'.
DIFXAPP: INFO: 'CustomActionData' property 'UI Level' is '2'.
DIFXAPP: INFO: 'CustomActionData' property 'componentId' is '{6125BDA1-74B9-443C-B130-494C60367EA4}'.
DIFXAPP: INFO: 'CustomActionData' property 'componentPath' is 'C:\Program Files (x86)\MyProj\Drivers\CyUSB\'.
DIFXAPP: INFO: 'CustomActionData' property 'flags' is 0x8.
DIFXAPP: INFO: 'CustomActionData' property 'installState' is '2'.
DIFXAPP: INFO: 'CustomActionData' property 'ProductName' is 'MyProj'.
DIFXAPP: INFO: 'CustomActionData' property 'ManufacturerName' is 'manufacturer'.
DIFXAPP: INFO: user SID of user performing the install is 'S-1-5-21-1332366759-4080576608-3295227165-1001'.
DIFXAPP: INFO: opening HKEY_USERS\S-1-5-21-1332366759-4080576608-3295227165-1001\Software\Microsoft\Windows\CurrentVersion\DIFxApp\Components\{6125BDA1-74B9-443C-B130-494C60367EA4} (User's SID: 'S-1-5-21-1332366759-4080576608-3295227165-1001') ...
DIFXAPP: ERROR: no driver packages found in C:\Program Files (x86)\MyProj\Drivers\CyUSB\
DIFXAPP: ERROR: InstallDriverPackages failed with error 0x2
DIFXAPP: RETURN: InstallDriverPackages() 2 (0x2)
CustomAction MsiInstallDrivers returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)

If I remove the <difx:Driver> tag then installation completes successfully and the .inf, .cat and .sys files all appear in C:\Program Files (x86)\MyProj\Drivers\CyUSB\ where DIFX is looking for them. I’ve not installed drivers before with WiX Toolset, please let me know what I’ve missed or if I should be taking a different approach entirely!

Thanks very much for any help!