Install Box Sync on PC using existing Box Sync folder
You have a published workaround here:
This only describes how to download the Box Sync data all over again. I do not have high-speed internet, so this would take weeks to do.
All I did was change out my storage drive. All of the Box Sync data was copied exactly, so all 50GB of data is still there. I just need to have it see that the files in the current folder are the same (you can use the filename, location, and file size). Syncing the file's timestamp with my PC would be a nice feature, as my PC is always the original.