I have LightRoom 6 as standalone. I tried to update LR as it won't open my Nikon D500 RAW files.
Now LR won't even open. I am running a MAC with OS X version 10.8.5.
What should I do in order to be able to :
1. Open LR 6
2. Be able to open the Nikon D500 Raw files?
With OSX 10.8.5, you cannot update beyond Lightroom 6.1. So you would have to update your operating system to install 6.6.1 and actually use it.
You probably need to uninstall Lightroom and then reinstall Lightroom 6 in order to use Lightroom at all.
You can use the FREE Adobe DNG Converter to convert the D500 Raws to DNG and then use those in Lightroom 6.