i've tried to bring the Raw back into LR - says it's already imported - won't let me re-edit.
That's right, once you import photos into Lightroom, you don't import the photos a 2nd time, there's no benefit, and it just causes problems.
To edit the photo again, you go into the Library Module (not the Import Dialog Box), find the photo, and perform more edits on it.
I am sorry for the inconvenience caused to you.
I would like to inform you that exporting a file from Lightroom does not remove the file from Lightroom catalog.
You need not to re-import the same file. You can access it from the previous location in Lightroom.
Let me know if this helps.
Yes, the external hard drive needs to be attached. Importing images into Lightroom is not a process of Lightroom ingesting the images. The images are never "in" Lightroom. Lightroom functions by using a catalog. This catalog keeps track of where the images are located as well as the adjustments that you have made to those images. The images need to be available from that location whenever you want to work on them.
Collections are simply a method to enable you to group images together by some criteria. The collections are stored within the catalog, and are only available through the catalog. In order for the collections to display the images they are supposed to display so that they can be edited, the images need to be available from where they are stored.
When the images are unavailable, as in your situation where the drive is disconnected, Lightroom still knows that the image has been imported. Lightroom has a preview image for that file. That is why Lightroom will not allow you to import the image a second time.
that's a great help, thanks.
i love LR but its a bit of learning curve.
Regarding the learning curve, an investment in time (but not money, see the links below) is well worth your time