I use Thunderbird and it's installed on multiple machines where I have it configured to access the same email account via IMAP. I never really had a problem wi

I use Thunderbird and it's installed on multiple machines where I have it configured to access the same email account via IMAP. I never really had a problem with out of sync mail and searches are done locally on the machine rather than on the server. I don't have it configured to use Maildir, but the files that store messages are in plain text and I could use grep on them if I wanted to.