when trying to accept an invitation to a shared folder, dropbox wants me to create a new account

Leslie

Here is the hard truth, based on the screenshots that you gave, and thanks a bunch for those, the invitation is not from a regular Dropbox account.  It could be that the other person has accepted a trial run of Dropbox for business or even a free Team account, but no matter, its another set of rules.  I will list a bunch of Help Center 
Articles at the end of this post for your review

Here are a bit of facts.  You would want to have a new account since once accepted, you lose ownership of that account,  Another point is after joining a Business team if the team admin decides to remove you from the team, the account is deleted.  It does NOT get returned to the previous owner.  So this is a different ball game, a different Dropbox experience.  I would recommend reading up on it to see if you want this.

HELP CENTER ARTICLES:

• Can I have two Dropbox accounts on the same computer or device?
• How can I switch the email addresses between my personal and business accounts?
• How do I connect or disconnect a personal Dropbox from a Business account?
• How do I move files between my two Dropboxes?
• How do I sign in to my personal Dropbox and work Dropbox on my devices?
• What happens when I connect a personal and work Dropbox on my devices?

Hi Leslie B.8,

From your screenshots, it looks like your friend invited you to join their team. Accepting the invite would change your account to a Business account. This does not sound like what you are trying to do. I would ask your friend to resend the invitation to join the shared folder following instructions here: https://www.dropbox.com/help/files-folders/share-with-others

Shared folders in business accounts may have restrictions on sharing out of the team. If this is allowed by the team admin, the user would see a warning that they're sharing out of the team, and the share will go through. If the admin has prevented sharing out of team, then your friend should talk to their admin about what they are trying to accomplish and why they need to share outside the team.