Your external hard disk and network volumes display in Lightroom's Folders panel under your Macintosh HD as folders. The top-level folder is named "/".
This issue occurs after you import images into Lightroom from the root of your Macintosh hard disk, using the option to add the images from that location. If during import, you choose to copy images to another location (other than the root Macintosh HD), this issue does not occur.
In this solution, you use the Hide This Parent folder option to move the volumes up the organization tree to their original positions.
In the example below, images were imported into Lightroom using the date folder organization under the Macintosh HD. The jump drive (also known as a flash or thumb drive) with imported images was added to show how external, removable, or network drives act in this situation.
The Folder panel below shows the initial organization, before importing from the root of the Macintosh HD using the Add option.
Move to another location all the images that you imported from the root of the Macintosh HD using Add. If necessary, use a Finder window to locate these photos. After you import them using Add, they are no longer listed in the Folders panel. You can move them in Finder, and then relink to them. The image below shows what the Folders panel looks like after you import an image from the root of your Macintosh HD using the Add option.
Notice that the jump drive is duplicated under the Volumes folder.
If you have any photos from the root drive still in the catalog, a warning appears. If you moved and relinked to all your photos, as in Step 1, no warning appears. If the warning appears, you still have one or more photos in the root that you have not moved. If the warning appears, click Cancel, and move your photos per Step 1. If you click Promote Subfolders, the images you added from the root are removed from the catalog. However, they remain in the root of your hard disk.
In this example, originally the date folders were directly under the Macintosh HD folder, so the User and Username folders did not display. To return to that organization, Ctrl+click the Users folder, choose Hide This Parent. Then do the same for the Username folder.
The remaining difference between this folder structure (image below) and the initial structure is that the Pictures folder now appears. It appears because it's part of the path to my date folders. All the date folders are inside the Pictures folder, but there are also loose photos inside the Pictures folder. If the Pictures folder is hidden, all loose photos in the Pictures folder are removed from the catalog. The same warning appears, as in Step 3. If there were no loose photos in the Pictures folder, hiding it would not remove any photos.