If you are trying to use Camera Raw with Lightroom, that won't work. Lightroom does not use the Camera Raw plug-in. The D810 is supported in Camera Raw 8.6 release candidate and the DNG converter 8.6 release candidate. That should indicate that it will probably be supported in the next release of Lightroom. In the meantime you could try downloading the DNG converter 8.6 RC and convert your raw images to the DNG format. Adobe has not announced when Lightroom 5.6 will be available.