As of now this is a known issue with the latest version of Lightroom, so I would suggest you to Roll Back to the Previous Version of Lightroom: Synchronize folder fails with error 'No photos or videos were found to import'
I did uninstall this version, but when I go to the links to install the previous version, they only allow LR 6 or 5 or 4, not CC. Where can I get the previous CC version?
You may install it from Creative Cloud itself.
Won't that install the latest version and not the previous version?
My understanding is that you can’t install an earlier version from Creative Cloud desktop – only the latest version; so launch Finder and use the installer in Applications to trash your present installation. Then download the original release. After installation apply the updates in order.
Download LR 6.0/CC 2015.0
Apply the 6.0.1/ CC 2015.0.1 update
Apply the 6.1/ CC 2015.1 update
Apply the 6.1.1/ CC 2015.1.1 update
It's usually a good idea to clean up what’s left behind after uninstalling.
I recommend trashing the prefs.
Launch Finder and click the Go menu whilst holding down the Option (alt) key. Then go to Library >> Preferences and clear everything relating to LR6 which usually means deleting the following files: