New iPad wont sync photos with MBP

I recently bought a new iPad 8. I have a MBP(2017) [please excuse typos - it has a scissor keyboard]. My previous iPad had no problems syncing with the MBP, however the new iPad will not. I do not use iCloud for photos. All of my photos are on my computer in Lr and once processed, duplicated into Photos. I have two Photos libraries, which may be the problem, but I can't see why. The original library (which I would like to copy) was called "Photos Library (original)". The name change was created by the MBP, when I brought in a second library that had been on Aperture, the other library has never had the name Photos Library. When I sync, I connect the iPad to the MBP and use finder, but when I click on the Photos tab I get the message,

"Photos cannot be synced to the iPad “Tim’s iPad” because your Photos Library could not be found. Open Photos to create or update your Photos Library."

The Photos Library was open at the time. Also, I have changed the name of the Photo Library from Photos Library(original) to Photos Library (having closed and reopened Photos). I have turned my MBP off and on again. There is an option to select a folder for syncing other than Photos, however, when selected, this will not find either a Photos Library type file, nor the LightRoom Library folder.

Does anyone have any helpful suggestions other than using the cloud?