Can I import the offline songs that I backed up?

[MackZanta]

I recently moved abroad to a country where all internet access is paid for per GB. Before I left, I had 15GB of downloaded/offline music which I backed up on an external hard drive just by copying over the folder that it was stored in. After getting here, my Spotify Desktop application refused to open so I downloaded a fresh install.

Now I'm wondering how to import my backed up files so that my offline playlists can once again be available without re-downloading all 15GB. I tried just going to Preferences and pointing "Offline Song Storage" to a folder with all the backup, but it erased it and started re-downloading it again. I've searched around online but seen mixed answers like in this thread. Any thoughts?