Can I back up my new external drive to Dropbox without re-uploading my old backup files?

Hey gordo169! Thanks for your post and welcome to our forum. 

If you use Dropbox Backup for the new drive, I’m afraid you’ll need to re-upload all of its contents from the start, no matter what happens to the old drive. 

The new drive is treated as totally separate to the old one, which is why your files will need to be re-added.

Let me know if you need something else, though.

Thanks Nancy.  I ended up having to get another new drive, empty, and am now restoring my backup to that drive so I can remove the old backup and start syncing the new one.  However, there are a couple of directories with deep folder nesting and lots of little files, and I'm hitting the max file limit big time. I understand a zip file cannot be created, but the prospect of drilling down and carving out bite-size pieces and reconstructing them is too painful to contemplate.  Is there ANY other way to download these?  e.g. I'd love to sync the new drive as is, then copy the directory on the web app from the old to new drive before removing the old one (I have the space), but I'm pretty sure I can't do that. I'm looking for any alternative, wanting to believe the promise of "easy restoration"!

Thanks for the update here, gordo169.

If you're going down that route, I think what I can suggest is downloading the files in batches.

If they are too many to download from the web, I'm afraid that's the only way to go about it.