Hello, I have an issue with Lightroom 5.7 under OS X Yosemite. My catalog and my photos are located on an external drive (/Volumes/Alexandre (Bleu)/Multimédia/...). All my files are online (checked) but strangely, when I want to synchronise a folder (for example with 100 pictures inside) (because I added one picture), Lr tells me that he have to delete 100 pictures and add 100 pictures, just like he considers that my original pictures are gone. Howerer, when I want to modify parameters of my pictures inside Lr, without dynamic preview, it works and it does not report any issue regarding the location of the file. I am a bit lost... Anyone encounters this kind of behaviour?