Your question is already answered, at least partly, https://www.reddit.com/r/Thunderbird/comments/kahww0/how_thunderbird_maildir_implementation_deffer/

If you want to archive mail, then a) if you are not (as you say) technical then perhaps you should like work within the confines of what is easily provided in Thunderbird, which is "Local Folders" b) it is good that you begin this time with the more open ended question/goal "archive and backup all my emails locally"

The answer to #3 is no, which makes #1 and #2 no longer relevant

1. 4 why would you do that? Is there a multiuser requirement to your goals, which you have not stated?

1. 5 No.

Your question is already answered, at least partly, https://www.reddit.com/r/Thunderbird/comments/kahww0/how_thunderbird_maildir_implementation_deffer/ If you want to archive mail, then a) if you are not (as you say) technical then perhaps you should like work within the confines of what is easily provided in Thunderbird, which is "Local Folders" b) it is good that you begin this time with the more open ended question/goal "archive and backup all my emails locally" The answer to #3 is no, which makes #1 and #2 no longer relevant

1. 4 why would you do that? Is there a multiuser requirement to your goals, which you have not stated?

1. 5 No.

@Wayne Mery, you seem angry, and clearly didn't read the whole thing. Why are you taking this personally!? Anyway, after reading my post, I see it had many grammatical mistakes, that is my bad, maybe that triggered your negative response. I am sorry about that.

>a) if you are not (as you say) technical I didn't say I am not technical, again sorry.

>b) it is good that you begin this time with the more open ended question/goal "archive and backup all my emails locally" It was not a question! That is how I currently use Thunderbird, it was just an FYI to give a background. I use Thunderbird to have a local backup of all my emails locally on my machine which is also intended as an archive, but I am not sure if the format Maildir used by Thunderbird is archival.

>The answer to #3 is no I am looking for more than "no," but please don't elaborate, again i am sorry.

>which makes #1 and #2 no longer relevant Still relevant, I am sorry don't be angry, please.

> 4 why would you do that? Is there a multiuser requirement to your goals, which you have not stated? why would you want to know? If you have read the whole thing, again sorry for the bad grammar, you would've known. Please don't be angry, just let it go, and forget about this.

Ask a silly question. Is where I am coming from. You are taking a direct and somewhat polite response to your questions as anger. It is nothing of the sort. However the premise of your question is fundamentally flawed to the point is in not possible to answer it without pointing that out.

Thunderbird is not a mail archiving platform. Those that attempt to use it as such are destined to failure. Archives are data archives and the storage formats used are common formats that will stand the test of time. That Thunderbird native MBOX format as well as the eml format used for storage of individual email are plain text than both stand a good chance of being readable data long into the future.

The ability of import or export data in any particular format to any particular piece of software as only predictable based on the platforms current capabilities. When I first used Thunderbird it imported mail from Netscape suite and Eudora. It no longer does either. SO if someone had based their archival decisions based on the format used by either of those products and Thunderbird's ability to import them would now have a serious issue.

Maildir is a server based email storage format designed for use by mail servers. that Thunderbird uses something similar (It is refered in the bug that implemented it a "maildir like") without any intent to make it meet the maildir standard is particularly relevant.

1) what are the differences between Thunderbird's maildir and standard maildir, and can it be converted?

False assumption. There is no intention to ever implement maildir as used in IMAP server implementations. See bug 58308

2) Why not have a standard Maildir?

That decision has been made, see my answer to 1. But fundamentally windows and mailDIr are incompatible. As windows is a primary platform for Thunderbird it will not be implementing maiDIr.

So in future users like me who wish to host their own mail server can just upload the email account folder in Thunderbird profile directly to the mail server (I have no idea about how to host my own mail server)

I would assume the mail server software's ability to import mail in various formats would be one of the criteria you would use to chose your server software. But it is not germane to a mail client such as Thunderbird how you might or might not get email into or out of a new mail server implementation. That is a server side decision unrelated to any email client.

3) Is maildir a good long term archival format, will it be readable by different software in future?

I suggest you consult someone that is knowledgeable about server software and mail servers in particular. While maildir is popular among the open source contingent of mail servers, I don't think Microsoft exchange server has the concept and I do not know if it is supported by the IBM implementation but I think not.

Personally I would suggest the EML format for local archives, as it is the simplest and most likely to have the longest ability to read the file, being text based is not dependant on a particular software being available. However we are already seeing issues with Windows text Vs Apple text Vs Unix text. So even now all text files are not created equal. Time may well paper over those things or turn them into chasms. I do not own a crystal ball. I am not in the business of predicting what data formats will be popular in 20 years. Next year Thunderbird will drop support for mail spool files (Linux only now) that is a very mail server centric format. But it is going away. Will the similarities between maildir and Thunderbird file per email implementation get closer together or further apart. This again is in the realm of needing a crystal ball.

4) Is it possible to convert the database to something that mail servers could you use in case I want to move from Gmail to my own hosted mail server ?

Everything is possible as long as you have the money for development and the specifications of the data storage format. Having said that, actually looking at the import and export capabilities of software is a good starting point. That is why there are consultants in the IT space. It is highly complex, and once you start with server hosted applications, fraught with difficulties that the layman is not really capable of adequately managing. This forum is not the place to provide expert advice to those making such implementations.

You might also want to look at bug 845952 There you will see Wayne filing the organizing bug for the additional work needed for the current implementation. You will also see there is a LOT of work still to be done..

My sincere apologies to both of you, I didn't know that Wayne Mery (wsmwk) is a contributor and it looks like you are too. Before I start, you guys have many post to reply to, but sometimes it is better not to, let other users contribute their knowledge because when you are busy and are forced to write something hastily it comes out wrong, maybe not to you guys but to the OP. Also,to you guys it is frustrating to reply to a "silly questions" (to me it is still not a silly question).

About Thunderbird not being a mail archiving platform, what do you suggest that is open source? Also, why TB shouldn't use a standard format that is used by other opensource email clients and mail servers?

(If anyone knows of a backup/archiving software that is opensource and use an archival open format that is popular, please suggest it, I couldn't find.

I hope that the Tunderbird's Maildir get as close to the standard Maildir which is popular.

But fundamentally windows and mailDIr are incompatible

I already read about this before I posted here, but the difference looked manageable, that why I would appreciate more details on this, don't get upset, you don't have to answer this, if I had time to learn all of this, I would because having my email archived is important to me, and I might be forced to do so one day. ONLY IF you have time give me more details. I also read your response several times, so I won't miss anything.

Anyway, from wikipedia article about maildir the only issue is that Maildir can't be used on Windows because windows don't accept colons in filenames then per that Wikipedia article it can be substituted with ";" or "-" which means it is easy to script your way to convert it to a standard maildir that will work with other open source software that support Maildir and I think, I am not sure, just an assumption, most open source mail server can read the standard maildir and because it is text based and popular that makes it a perfect archiving format, to my silly mind.

Also, the support article https://support.mozilla.org/en-US/kb/maildir-thunderbird don't explain the decision and the difference with standard Maildir, it would helps me and I assume other users in future to know why Thunderbird went for a non-standard implementation and why? And what is the difference? is it just that colon switched with a different character?

Lastly, having a standard format used by Thunderbird that is opensource and used by other Email clients and mail servers make Thunderbird more attractive. Again my sincere apologies to both of you and I appreciate both of you, thank you.

PS, For others coming here: still didn't find away to archive my emails with remote content, and if you are developer of Thunderbird, I think having the option to download all remote content and archive it in a folder that Thunderbird go revert back to when the remote content is not available would be an attractive feature.