Having just downloaded and installed Lightroom 6 I still cannot import RAW files from my A7R2 to Lightroom despite it apparently being supported?
Please update the Lightroom to the latest version , i.e Lightroom 6.1.1, and then you would be able to import the images in Lr.
Please let us know if it helps.
You should use Help / System Info to check what version of LR you’re running.
If you are still running an older version (i.e. LR 6.0) then try Help / Updates and/or Help / Sign Out then Help / Sign In then Help / Updates, to get LR to find the new version. It might also require a reboot.