We may expire passwords from time to time as a proactive security measure to protect accounts. Accounts may be at risk if suspicious account activity is detected or passwords are exposed. Passwords can be exposed by a different service, phishing, or malware. You’ll need to update your password before linking a new computer, phone, tablet, or API app.
If your password has expired, you’ll see this screen the next time you sign in to the Dropbox website:
Enter the email address associated with your Dropbox account on this page, and we’ll send you an email to change your password.
We highly recommend using strong, unique passwords across services.