How do I re-install Lr6 after having to unistall it?
If you have Lightroom 6 as a Standalone software, then refer the below link to download it and then install, Once its installed enter the activation key to activate the license.
Download link:Install Photoshop Lightroom
However, if you have subscribed to the Lightroom CC 2015, then open the Creative Cloud Desktop App >> Go to the App section >> look for Lightroom and install.
Let us know if that helps.
Retrieving data ...