How do I fix WiX warning: Component 'X' has both per-user and per-machine data with an HKCU Registry KeyPath

I'm trying to maintain some Wix code, and am getting the following warning:

warning LGHT1076 : ICE57: Component 'FILE_MY_ASSOCIATION' has both per-user and per-machine data with an HKCU Registry KeyPath.

From the following code:

<Component Id="FILE_MY_ASSOCIATION" Guid="E1DF42A5-BD00-4a80-9BE5-B66A3EF0576E" Win64="$(var.Variables_Win64)">
  <RegistryKey Root="HKCU" Key="Software\MyComany\MyProduct">
    <RegistryValue Value="" Type="string" KeyPath="yes" />
  </RegistryKey>
  <ProgId Icon="FILE_MY_FILETYPE_ICON" Id="MY_FILE_EXTENSION" Description="My Product File" >
    <Extension Id="myext" Advertise="no" >
      <Verb Id="Open" Argument="&quot;%1&quot;" TargetFile="MYUI_EXE_FILE"/>
    </Extension>
  </ProgId>
</Component>

I'm having trouble working out what's wrong or if this is a warning I really need to worry about.

• Do I need to worry about and fix this warning? Could the code as it is currently cause problems in some circumstances?
• Also, I'm wondering, why does the registry key use HKCU instead of HKLM. If I change it to HKLM. the warning goes away, but does this affect the behaviour of the installer?

Thanks.