Well, the standard format in Thunderbird is mailbox and these are the usual extensionless files in a Thunderbird profile.

However, you can now elect to use a form of maildir, but I haven't been in a position to use this myself (it's only offered with newly-added accounts; there is no migration for existing accounts) and my reading on the topic leads me to understand it's incomplete and not (yet?) available in IMAP-connected accounts. Possibly the absence of search integration is another shortcoming.

I don't have a Windows machine here to check with, but Thunderbird does offer Windows search integration with its regular mbox files; it generates mozmsgs folders containing files with the wdseml extension, which Windows search can use.

You said "maildir" so I suspect this won't help you, but you could look through Tools|Options to find a setting to enable the search integration feature. TBH, I assumed it was enabled by default.

Zenos said

Well, the standard format in Thunderbird is mailbox and these are the usual extensionless files in a Thunderbird profile.

As explained, I do not refer to the (dinosauroid) maildir format, but I have installed Firefox 38.0.1 because it advertizes maildir as one of two new top features. Certainly I use maildir. The files without extension are not the mbox files, but the individual .eml files, missing the extension .eml (BTW, .eml is a mbox containing ony one mail).

... leads me to understand it's incomplete and not (yet?) available in IMAP-connected accounts. Possibly the absence of search integration is another shortcoming.

Certainly it is available in IMAP. Just has to be enabled in the settings. And yes, it is only for new accounts. However, just delete the account, and add it again, takes 5 min. The mails are on the IMAP server anyways, local is only cache.

... Thunderbird does offer Windows search integration with its regular mbox files; it generates mozmsgs folders containing files with the wdseml extension, which Windows search can use.

As written above, the attachements are stripped from the .wdseml files. Weird idea, but that it is, and thus this feature is useless for me.

You said "maildir" so I suspect this won't help you, but you could look through Tools|Options to find a setting to enable the search integration feature. TBH, I assumed it was enabled by default.

It is enabled, by default. But see above.

Thank you for trying to help, but I think I will deinstal Thunderbird again. From a technical point of view, Live Mail is still the only email client for Windows with resonable mail storage, despite it has almost no features and a very unstable imap connection.

It would be so easy to use the proper extension .eml for the files in Thunderbird's maildir format. Maybe some of them see this thread.

1. Windows Search Integration is not the default. And it has a performance pentalty. Therefore, since it's useless to you, you should disable it.

2. IIRC, Windows search does not by default index things in AppData, and Thunderbird profile is in %appdata% (AppData\Roaming). I suggest you set Windows to index %appdata%\Thunderbird\Profiles\<yourprofilename>\ImapMail\ by right clicking on ImapMail, properties, Advanced, and enable "Allow files ... to have contents indexed...". That still leaves you with the issue that the files don't have an extension and therefore you don't have a subset category for mail. But they _should_ still show up in a search of file contents.

Thank you, I already did point 2, did not work. Microsoft (at least a community moderator) says at http://answers.microsoft.com/en-us/windows/forum/windows_7-files/add-files-with-no-extension-to-index/e9666811-5486-4311-bbb8-767e550f6e52:

"...there's no way to index a file without an extension."

"The trouble with this is that files with no extensions, as far as Windows is concerned, are not files. And since they have no predictable internal structure, there's no way the search system can index them, it doesn't know what it's looking at. There really isn't a way around this, unfortunately."

Please note that a file extension has a completely different meaning in Windows than in Unix. While in Unix it is just a dot with a few characters afterwards, in Windows it is the one and only specifier for the file type. A file in .eml format should have a .eml extension, otherwise problems are unavoidable.

Well, this is a clumsy workaround, but you could create hard links to the files in the Mozilla folder, and rename each hard link adding an .eml extension. But then you'd have to repeat the process to get an .eml file for the new emails.

Did you find any new info on your question? Have you found a satisfactory alternative?