I have all my photos in folders on an external hard drive and LR5 puts a ? on every folder even though the ext hard drive is connected to my MacPro. it sees the files and all the adjustments I've made. but why does it not see the folders on the ex drive and think they are missing? how can I correct this? thx
This happens because the files (or the folders that contain them) have been moved, renamed or deleted outside of Lightroom ... or you renamed the drive outside of Lightroom.
The solution is found here: Adobe Lightroom - Find moved or missing files and folders