Yes. If you've received an invitation to a shared folder, you need to have a Dropbox account to join it. This is because files in a shared folder are synced between members.
This is different than read-only shared links to a file or folder. With read-only shared links (which aren't synced between members), recipients can view and download folders and files as local versions on their computer.
If you don't have a Dropbox account, or don’t have a Dropbox account registered to the email address where you received the invitation, you'll need to either:
- Create an account, or
- Ask the owner of the folder to send a new invitation to the email address for your existing Dropbox account