When I export a picture, sometimes I get the error "?:0: attempt to perform arithmetic on a nil value" . My Lightroom version is 5.7. How can I fix this problem? My catalog contains about 75 000 photos.
Thanks for your help.
incorrect data in the lr catalog may be the reason for this. Try to save the metadata for the photo (Ctrl-S, Cmd-S), delete the image (remove from catalog) and sync the containing folder (import image again). Perhapst this helps.