Thanks.
The labels in the list could be moved all-at-once by editing a config file, but as there are only 8 of them it's probably easier and safer to do it the normal way, by assigning labels in the new place.
I'm assuming those 8 labels weren't all of them, and the others are missing entirely?
A quick explanation of how labels work is needed:
[ul][li] When set to be stored in the file system (as they are by default and are in your screenshot), new labels will be stored with the files themselves if possible. (The main requirement is that the drive is NTFS and not FAT32 or a non-Windows network share). Those labels will move with the files but only if the destination drive can also take them (e.g. it has to be NTFS as well) and if the Copy Metadata (comments, keywords, etc.) option is on.
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[li] If not set to be stored in the file system, or if they can't be stored (e.g. because it's a FAT32 drive), the labels are stored in your actual Opus config. Those labels will not move with the files, and always point to a particular path rather than a particular file. (That has its advantages sometimes, so you can override how a label is stored, too.) (In older versions of Opus, this was the only way to store them.)[/li][/ul]
Only the second type of label will be listed in the Preferences window (since labels stored in the file system aren't part of your configuration, and Opus doesn't known about them until the folders they are in are actually read).
If there were other labels than the ones in the list, they will unfortunately be lost if the files were moved with the Copy Metadata option turned off, unless there's a backup of the folder/drive they were in which includes NTFS alternate data streams.