Move Photos Library to NAS

I am trying to move my wife's Photos library to my NAS but I keep getting a finder error that says some of the files cannot be read and not all of the photos will be moved. I have the share mounted on her Macbook Pro and just tried to copy and paste and it gets about 90% done and then gets the error. Is there a trick to get this to work? I moved her iTunes library easily but this won't work. The NAS is an Austor and formatted with EXT4 but AFP is active so I don't think that is an issue.

If this won't work I guess the next thing is to get a WD External Cloud drive?? Her photos take up 60+GB of her hard drive and I need to make room.

Thanks