Pluggable Stores explains why we need other pluggable stores. Maildir is the first pluggable mail store to be implemented as an alternative to mbox - the traditional format used by Thunderbird. Thunderbird's maildir implementation allows a single unique filename per email (EML). HOWEVER, note this is NOT full maildir in the sense that most people, particularly linux users or mail administrators, know as maildir. You cannot point a Thunderbird account to a mail server directory. You do not get message flags stored with emails. You only get a single file per message, and nothing more.
Enable Maildir mailbox format
If you want to experience maildir, you need to set the string pref "mail.serverDefaultStoreContractID" to "@mozilla.org/msgstore/maildirstore;1".
Though, we aren't sure of the side-effects of using maildir as the default store on a profile that was created on Berkeley mailbox(mbox) format; so we suggest you to create a fresh profile to work with maildir so as to avoid any dataloss that might occur.
Operations now successful with Maildir
There are still a few issues left to be addressed with maildir implementation. But a number of issues were addressed. So far,
- The pop3 filters work reliably with maildir. See bug 827048
- All local folder operations are successful with maildir now. See bug 1028548
- Movemail download now works with maildir. See bug 1027947
- Sub folder directories are created at the expected place now. See bug 1017939
Operations still unsuccessful with Maildir
- See meta-bug finish "maildir" message storage
- Quarantine filter moves now work with maildir. See bug 1044456
- Move to maildir local folders sometimes fail. See bug 859011, bug 1215722.
- Rename of IMAP folders is in progress. See bug 857436
- Crash [@ OOM | small ] during generating MSF file. See bug 1333342
Methods that may result in Process crash
Please don't use CopyService for any copy operations in the source code if you are using maildir. As of now, we haven't addressed this bit and copying using CopyService results in process crash.