A Junk folder should be created automatically when it is needed. So I would check the settings of the affected accounts to see where they are set to send their Junk messages. If they have been set to use another account's Junk folder, or not to move their Junk then those account won't need A Junk folder.

You mean the Junk messages go in the Junk Folder? If I log into hotmail.com/outlook.com and look at the email that does not have the Junk folder in Thunderbird, it has 6 unread messages in a folder labeled Junk, much like the 3 emails that have a Junk folder in TB.

Please think when you write "email". Email what? Message, account, server?

Are you using IMAP? If so, have you tried subscribing to that Junk folder?

What settings do you have for the handling of junk mail in Thunderbird?

What I meant there was an email address.

In my picture, I have the top account which does not have a Junk folder in Thudnerbird. Accessing that SAME email account at the original web browser client, like Outlook'.COM I can access a Junk folder. That Junk folder is NOT available in Thunderbird. However, for other email accounts also hosted on Outlook.COM, Thunderbird does show the Junk folder.

If there is a way to subscribe to the Junk folder, I'd love to hear it. As far as I can find, it's not an option when viewing my email account on Outlook.COM' in my web browser.

In regards to "handling of junk mail in Thunderbird":

https://imgur.com/a/FIFBf

So it's the same thing, right? Cool.

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But now it looks like what is in common (I thought I checked this before, but it was in the middle of other projects -- this was actually a distraction from what I was initially working on; I just needed to click a link in a Junk folder which was unavailable in TB for that email account) is that only the IMAP folders have Junk folders.

Is there any easy way to convert from POP to IMAP? Because just changing it under the "Server Settings" feature doesn't work. I fear I'd have to delete the account on TB and then readd it. What will be the consequences of that? Losing a history of which emails are read vs unread?

Both IMAP and POP connected accounts in Thunderbird can and do normally have Junk folders. But POP can see only the Inbox folder on the server. If your provider is unhelpfully putting messages into a Junk or Spam folder and you use POP then you won't see those messages. The rational thing for them to do would be to label the spam and leave it in your inbox. But then most email providers want you to use webmail so they get revenue from their advertisers, so hiding your junk or spam gets them some leverage to have you go to their website.

Note that in your first picture neither of those Junk settings is enabled; the check boxes are both empty.

Why do you not use the "add images:" option on this site, rather than asking us to go off to a 3rd party site with lurid advertising?

Do NOT change the server settings to convert an account. Set up a second instance, but using IMAP this time. Then, assuming you don't want two accounts in Thunderbird for one address, move messages you want to keep from the old POP-connected account into either Local Folders or the new IMAP-connected account, and then you can remove the old POP-connected account.

But bear in mind that POP and IMAP have significant differences. Read up on them and make sure you understand what you're letting yourself in for. People whose habits have formed around the use of POP can have a hard time adjusting to IMAP.

I haven't had any differences to my knowledge, but then again, I only receive emails on IMAP accounts. Only the POP accounts do I send emails from.

Regarding using a 3rd party site: 1) I have Adblocker so I don't know how ad-plagued that site is. Apologies if it's atrocious. 2) I Can upload a clipboard image to that site; I have to save a file and then upload it here for the image adder. That's a pain. I like Snipping Tool and pressing Ctrl+C to copy it to clipboard, then Ctrl+V on the third party site to upload it.

Thank you for the information and your time.

A few basic differences: POP accounts can only see server Inbox and emails are downloaded and stored in Profile. So any emails moved to other server folders by server or via webmail will not be seen nor downloaded. Option to leave emails on server or not has no effect on emails in Thunderbird profile. If you delete any email via eg: webmail, this has no effect on emails already downloaded. Folders created in pop mail account do not appear on server as they only exist in your Profile folders. Pop mail accounts will see a 'Junk' folder if 'Junk Settings' say put junk/spam in 'Junk'. Emails sent from a POP mail account are stored in that pop mail account on computer; they are visible in webmail.

IMAP offers a remote view of folders on server. You need to subscribe to see folders. Junk is a Thunderbird term - server usually call this 'Spam' or 'Spam items' or similar. You have to subscribe to see it and then tell Thunderbird to use it. Delete an email either via webmail, other device or Thunderbird and email will get deleted off everything as they are all one and the same folders. Emails are not necessarilly downloaded and stored in your profile, this will require account settings to ensure it occurs. Folders constantly synchronise with server to maintain same view. Accidentally or intentionally change server settings to point to another server will wipe out all emails stored in imap folders as those emails do not exist on the new server settings. Hence if changing eg: webhost, but keeping same email address, imap accounts should ensure emails are downloaded and then stored in Local Folders mail account before changing any server settings of the imap mail account. This is also the same if you intend to change ISP and therefore lose email address. Emails sent from an Imap mail account are stored in imap Sent folder and so are visible via webmail or other devices/computers.

Images :- I never bother clicking on links to images. I used to, but either images get removed or you cannot get access or they are plagued with ads.

Images need to be added so they are instantly visible. It may be a couple of extra clicks to you to post a couple of images in a manner that was preferred by volunteers, but how many additional clicks would a volunteer need to use when they are looking at a lot of questions. As it is you who requires the help, it would be helpful to volunteers if the image was actually displayed.

I still had to click on the image Zenos posted so I'm not sure what you mean by saving clicks. With an imgur album in particular, that saves a click as two images are displayed simultaneously; no need to click on two thumbnails.

In general firefox is not too great at uploading images with the Windows Explorer to jump around folders, so I am really averse to using it. Sometimes it slows down my computer something terrible while it twiddles its thumb on bringing up the folder navigator.

Thanks for the explanation regarding POP and IMAP.