Hello,
While not a tutorial, this blog post from the LastPass Blog does detail good steps to take to "clean up" your Vault and passwords: https://blog.lastpass.com/2018/04/spring-cleaning-digital-life/
There isn't a way to change multiple passwords at once in LastPass, although if you are changing a site's password on the site and a matching site entry is stored in your Vault then LastPass should pop up and ask if you'd like to update the entry in your Vault when a password change is detected.
RachelO is a member of the LogMeIn Community Care Team.
Was your question answered? Please mark it as an Accepted Solution.
Was a post helpful or informative? Give it a Kudos!
