One of the most popular email services, Gmail keeps track of all your emails with threaded conversations, tags, and Google-powered search to find any message you need.
Store the original email beside each named attachment.
Your marked client or case emails go into the shared archive beside their attachments, with a folder link for the filing owner.
Place flagged project attachments in the right folder and flag conflicts.
Your flagged email attachments go to the archive folders you set up, with original filenames and a report of files needing attention.