If you have them, they ought to be in your profile. I've never used the KLS tool, since backing-up the Thunderbird profile is a simple business of copying part of a folder tree. It doesn't need sophisticated tools. Also, if I want to move or transfer files between platforms, say from Windows to Linux, then platform specific-tools are of no use to me.

So, find your profile and see what's in it.

https://support.mozilla.org/en-US/kb/profiles-tb

Note it is hidden by default.

Now, had you moved any mail store folders outside the profile? Some users change the "Local directory" setting in an attempt to move mail stores to an alternative location such as a bigger HDD. The problem with this adjustment is that the backup program doesn't necessarily know where you have put the folders, and so just backs up the material it finds in the default location.

I've found my profile in OS(C):Users\Michael\AppData\Roaming\Postbox\Profiles\4ea24r4k.default\Mail\Local Folders\Inbox\'Name', where Name is sender name such as Amazon.mozmsgs. When I click on this name, the list of messages appears with an alphanumeric string title, a date, a type (Thunderbird Document) and a size. When I click on the individual message however, nothing happens. When I right click on it to 'Open with' Thunderbird, still nothing happens.

So, as I said before, it looks as though they are all there, but I can't open them. Any further advice would again be most appreciated, firstly to open them and then restore them so that they appear in the email programme itself in the appropriate folders.

Alas, *.mozmsgs are summary files put there to facilitate Windows' search.

You messages are stored in files (yes, files, not folders) without extensions. Typically there will also be an associated *.msf file, which Thunderbird uses to display the list of messages, and there may be others such as those you mention.

So, for instance, you would have, if all was backed up, a Mail folder, and in that, a Local Folders folder, and in that:

Inbox Inbox.msf optionally, Inbox.mozmsgs

and of these, Inbox is the only important file. The others can be re-created from it if they are absent.

Subfolders are represented by *.sbd folders, which will contain files representing your Thunderbird folders, along with *.msf files and again optionally, *.mozmsgs folders containing *.wdseml files for windows search.

So if you have, say, created a folder named Dave for correspondence with your pal Dave, there should be a file somewhere named Dave, and another beside it named Dave.msf. There may be copies of discrete messages in the Dave.mozmsgs folder, but these are likely to be be incomplete copies.

Here on this Windows 7 machine the *.wdseml files inside the *.mozmsgs folder open in Thunderbird after double-clicking on them. They may or may not be legible in a text editor; many will be swamps of html coding, others will be base64 encoded and quite illegible until decoded. The Notepad++ editor can apply base64 decoding (and other encodings) to read text if desperation sets in.

Note that for all of this, you really need the idiotic Windows default action to hide filename extensions to be disabled.

I've found someone reporting a similar problem on mozillaZine back in 2009! They solved problem as follows:

"It appears that the *.mozmsgs folders and *.wdseml files are created to integrate Thunderbird with Windows Vista Search. These folders and files are created in a manner that allows Windows to index them.

I copied the missing files from the *.mozmsgs folder in my profile to a new folder. Used the command prompt to change the file extension from .wdseml to .eml and then used Import/Export Tools Add-On version 2.3.2 to import the missing messages back into Thunderbird."

Can I have your opinion on this supposed solution before I steam ahead and try it?

I can't see it doing any harm. Of course, you shouldn't need to do this.

You may find that longer messages are incomplete (truncated) and that attachments are absent.

Did your back-up not contain the full Local Folders? Hard to see why it should specifically omit your subfolders.

Had you moved message stores by changing the Local Directory settings?

This is working but is proving time-consuming, even though I am able to use a batch extension renew software. The other strange thing is that I appear to be retrieving only emails filed before January 2014, which of course are of little value now. I have no idea where these come from; I can only assume I've accessed an old archive, but its title suggests it is much more recent.

Re Local directory settings, I do believe I set up Local folders that were different to the generic (yellowy/orange coloured) Inbox and Sent ones. Can't remember why i did this, but perhaps it's possible that the backup didn't access these, which would leave me with no recently filed emails. Not the end of the world, as I probably file a great many emails that really have no particular value.

If I establish anything else, I'll let you know.

As I have only been able to recover from back-up only old sent and received emails - again, I've no idea why this is - I decided to delet them all and start again.

Thanks Zenos for your input.

I think that the reason you only have old WDSEML files in your mozmsgs folders is that at some point you probably switched off the Windows Search functionality in Tools Options Advanced General. It creates duplicates of your messages in WDSEML files, probably without attachments that can be searched by Windows. Switch it off and they will stop being created but will not disappear.

I hope you did not use the procedure you describe to recreate mail folders of the same name as the ones that are missing because that will have overwritten your missing folders. As Zenos said the Thunderbird mail folders are called simply Foldername and Foldername.msf and it is the plain Foldername hat contains your emails.

I could add that you need to look in your original backup to see if the Foldername and Foldername.msf are there if you think that the format was the same as Thunderbird. If they or something like them are not in the backup then I guess they are not there.

Hello Guys

I do appreciate all your input, but this has proved too difficult to resolve and I'm now resigned to having lost the backdated emails.

I'm officially declaring this thread as closed from my perspective.