It sounds like you might have this backwards? The Browse tabs shows paths of folders that have been added to your catalog. You use 'Update folder location' tells the catalog where that folder has moved to (Here's the documentation page on that feature).
Perhaps this old thread is helpful: https://forums.camerabits.com/index.php?topic=14191.msg70238#msg70238
Getting things backwards is my specialist skill. I was confused here as the Browse window was showing some drives in their new locations & some in their original locations.
The old Mac had these internal drives:
Pinky
Perky
Mercury
Scratch
Raws (containing 2 large subfolders)
The new Mac has these, all external with subfolders as shown:
Mickey
Mercury
Minnie
Pinky
Perky
Scratch
Raws 1 (with one of the original subfolders)
Raws 2 (with the other of the original subfolders)
The Browse window shows:
Raws 1 & Raws 2 with all the files now in the catalog as should be.
Pinky is shown as a separate volume although it is a folder on Minnie. The files are all shown in the catalog and are really the ones on Minnie, not the old machine.
Perky is shown as a separate volume although it is a folder on Minnie. The files are all shown in the catalog and are really the ones on Minnie, not the old machine.
Scratch is correctly shown as a subfolder on Minnie but the files in it are shown as offline. Rescanning doesn’t change this.
Mercury is correctly shown as a subfolder on Mickey but the files in it are shown as offline. Rescanning doesn’t change this.
I considered doing a catalog sync in the hope of adding the files on Mercury & Scratch but the window currently shows the old paths. Is it safe to delete all of these, add the new paths and sync?
Why are Pinky & Perky shown as volumes & not as subfolders of Minnie. Does it matter?
David