Find third-party 32 bit product on 32 and 64 bit machines

I'm authoring an MSI file that installs an add-on to an existing application that I find via its HKLM\Software\... key using the RegLocator table; this works quite well on 32 bit 开发者_开发知识库Windows.

On 64 bit Windows, however, the key can be found under HKLM\Software\WOW6432Node\...; this is obviously correct as the other application is a 32 bit application, however it makes the RegLocator stumble.

Is there a way to check both the original and the rewritten key path, and use the first one that exists (if neither key exists, the component should not be installed at all)?

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Hmm, according to the documentation of RegLocator table, if you don't set the msidbLocatorType64bit of the Type column, it will search in the 32-bit portion of the registry. Otherwise it'll search the 64-bit part. So, if your third-party is always 32-bit (at least that's what I understand from your question), you can leave that bit unset and it'll always look into 32-bit hive.