Right now using the "Custom File Name - Original File Number" option when exporting photos only works if the file number is still at the end of the original filename sequence. A round trip to Photoshop changes the file name by adding "-Edit" on the end. This should be changed so that the export process uses the original embedded file number, disregarding the "edit" which has been added by LR anyway. Otherwise LR itself is creating a name that does not work in another part of the same program. (I find that most of the images I want to export are the ones that have been to PS, so that I can easily back up the changed images, the ones with bits that are not recorded in the LR catalog.) Thank you Adobe!