What exactly happens when you synchronize a folder: Synchronizing Folders in Lightroom « Julieanne Kost's Blog
Does it show a number of new photos in the synchronize dialog? When you then forward to import, what exactly happens?
A screen capture would maybe help.
Take care with synchronizing: The Dangers of Synchronize Folder | The Lightroom Queen
LR finds none to import because they have previously been imported.
You need to reconnect the photos in Lightroom (not import or synchronize) using these instructions Adobe Lightroom - Find moved or missing files and folders
I'll take a look, but the folder and the files are in the LR list, so they are synched.
When I right click to sync on the folder, it discovers all the images. When I say to go ahead with it it does calcs and comes up with the answer that there are no images.