I have over 4000 photos showing the "Not Backed Up, Corrupt Original" alert, all the images are present on my drive and as far as I can tell, not currupt. Like others I have seen report this issue, my images are stored on a NAS, it is hichly impractical to store all these images locally.
Unless a solution is already out there, I am requesting a re-sync feature to be added to lightroom, as mannually deleteing and re-importing my images is incredibly time consuming/frusterating a leave room for error and loss of work.