You've tripped over a very old LR bug that Adobe has never bothered to fix -- LR doesn't properly handle case-insensitive file paths (i.e. Windows and Mac paths). To fix this, first backup your catalog (as you know). Then in the Folders panel, right-click a top-level folder and select Show Parent Folder. Keep doing that until you see "users" (any case) at the top level. Then follow the steps described here: Re: Importing Problem.
Do you mean these steps?
1. Backup your catalog, just in case something wrong.
2. Create a dummy (i.e. new but empty) folder at the root of your MacintoshHD drive, call it something like "Dummy Images".
3. In the Lightroom Folders Panel right/ctrl-click on "My Lightroom Images" and in the resulting context menu select "Update Folder Location". A file browser window will open, use this to navigate to and select the "Dummy Images" folder. Don't be alarmed when "My Lightroom Images" disappears from the panel to be replaced by "Dummy Images", and all the sub-folders will have the "?" mark to indicate they're missing.
4. Next, right/ctrl-click on "Dummy Images" and again select "Update Folder Location".This time browse to and select the "MY LIGHTROOM IMAGES" folder, and if all goes to plan you should now see everything back as it should be, with "2014 Photographs" showing with the other year sub-folders. One thing to note, there MAY be a "Merge" warning message, i.e. along the lines of "This folder already exists in the catalog, do you want to merge", if so choose "Merge".
Right. Substitute your folder "Name" for "My Lightroom Images" in those steps.
Thanks for this. I need a small respite from doing battle with my computer, but hope to give it a try this week!