SPAM and junk are terms that are generally used interchangeably, especially in the IMAP context. But there is a subtle difference. SPAM is unsolicited commercial email. No such definition exists for Thunderbird use of Junk. I think the "idea" dates to Netscape Communicator (which I loathed because it was so slow) but it is not an issue worthy of a lengthy debate as popular culture basically uses the two words interchangeably.

Why do people use such unprofessional terms? It is Spam.

Actually is is whatever the mail server designates the folder name to be in the context of IMAP. I would direct you to this bug which is under development at the moment where some of the subtleties of the issue are covered. My opinion is that everything that has been done to standardize the names used as your suggest has done nothing but complicate the issue. Yahoo used the folder name "bulk" rather than junk or SPAM, then used something else in their webmail just to really confise their users.

Even "Folder" is childish to someone who started with Dos 5.0 although it is sort of correct.

DOS used the term directory, something Thunderbird still uses in account settings for the location of the files for an account the "Local Directory". OS/2 and MacOS used the term folder to describe the same thing. This is also a context issue. In the Unix world there is no drive C: as such mount points designate volumes and they are virtual. We may feel that words used to describe something are "wrong" or "childish" but that does not make them incorrect. I offer bug as a perfect example. In it's original mainframe context it meant literal a creepy crawly (insect) that had got loose in the circuitry. Now if an application does not work as someone expects, they call it a bug. Often when the application is functioning exactly as designed.

I just find it weird and confusing that there is no convention followed.

It is that you do not know the convention used, not that there is not one.

Thunderbird allocates the special folder icons based on a number of criteria. The most basic is history. When Thunderbird was first released, most accounts were POP and Thunderbird was coded to use the terms and folder names of Junk, Trash among others for POP accounts. IMAP introduced a complication as in that context the server gets to designate the folder names for "special folders" using the IMAP list command. See https://www.rfc-editor.org/rfc/rfc6154.html#section-2

So you see you think this is a simple case of everyone standardizing on a term. But what is the drafts folder actually called in say simplified Chinese or Romanian. The system does not care, as long as the folder is flagged with the drafts flag. This is a global community of users and standards and you might find the fact that you don't get to designate the icons to be odd. but as they follow purpose, you do have some control. In a pop account is you create a new folder and then designate it to be used in account settings as the draft folder, the icon will change on the user interface to reflect your change. In the case if an IMAP account you may find a duplicate use of the icon as your account settings say the folder is one thing and the server days it is another, so both get marked, but the server will follow it's rules, not Thunderbird's. So it will place spam mail into whatever folder it designates for SPAM.

So you saw a brief notification of a mail arriving. Have you looked in the windows notification center for the full details of the notification?

Thanks with your extensive explanation.

Although I did read it all and do appreciate it I do not feel any different.

Decades ago I was enthusiastic about the details of computing. Now I only want to do what is necessary as I have far more important things to do and you can only retain an interest to that depth for a certain number of years. My current "need" is to prepare our house surroundings for the snake and fire season. Currently stopping for a cup of tea and a bite to eat.

My experience is that in the last few years running a home computer system has become far more complex due to a variety of factors, not the least of is having to seek support for dealing with new features/bugs/stuffups, call them what you may. I have just given up on a Firefox issue that nobody has a decent answer for and don't even seem to truly understand except for one possibility that I will not really have time to learn about in order to implement it.

I have checked Windows notifications and it reports nothing new. The email seems to have completely disappeared. I don't recall having a single email going missing like this before.

Anyway I just wanted to know about the handling of junk with no junk folder and as it was most likely junk anyway it is likely not important.

Thanks for your time and patience.

All I did was explain. I don't really care if you accept the explanation and I certainly had no intention of changing your mind. However this is a support forum so I explained how it works and why.

There is also an Idea and feedback forum. It is linked to from the same Thunderbird help menu as this support forum. If you wish to suggest change or have feedback, that is the venue to do so. Perhaps a part of your frustration is you are here in a support forum putting forth your idea on how things should work and no one is interested. The same goes for your "firefox" troubles. They are telling you how it works and what do do to modify it to your liking and you are expecting someone to say "good idea". That is not going to happen in a support forum, especially a peer support forum such as those sponsored by Mozilla. It might happen in a feedback or ideas forum. Perhaps you should try suggesting your changes instead of seeking support you do not want.

I understand what you are saying but I take exception at " instead of seeking support you do not want."

Just because you could not help me with the issue of where that email went does not mean anything of the sort. You explained what I was asking. That sentence was completely false and uncalled for. I appreciate your assistance but I don't appreciate you taking your frustration out on me by making false claims. At no point did I say I did not want the support I asked for. It was the email that I said was likely not important. That would be the email that you could not provide help with.

In my world what I said was an acceptance of what cannot be solved and moving on.

We are supposed to be nice to you support people but that is a two way street.

Apologies, but you are asking how long is a piece of string. Now you want to discuss the semantics of that. I am done.

You LIED about what I said and now you offer a complete non apology for your disgusting behaviour.

Non apology not accepted.

For anyone interested, I have discovered what happened to the email. Thunderbird did not display it for several hours. It was just not visible anywhere until it suddenly appeared. Just saw it happen to another deleted email. I clicked on the bin folder and it was not there several hours after deletion. Clicked on another mail folder, then back and it was there. I also realised this has happened numerous times lately. Just need to do the right quick step first.