For anyone else who comes across this… It seems as if the error was caused by the Wwise 2018.1.0.6714 Unreal Project Integration. Adding xlar8or’s fix ended up revealing a mess of missing files. If you aren’t wanting to install Wwise as an engine plugin, an upgrade to 2018.1.1.6727 AND the “string DXSDK_DIR” patch should do the trick.