You have Junk controls enabled so that any emails which are thought to be Junk go into the Junk folder by default. I understand that missing emails can be frustrating to say the least, but checking the Junk Folder daily only takes a few moments.

Having Junk controls is not idiotic as the majority of users require this if they do not want to trawl through an Inbox containing Junk mail. I certainly have no spare time to manually delete or move junk mail and therefore no preference to sit looking at a load of junk interspersed through all my good mail, but if you prefer this then switch Junk controls off.

The purpose of holding them in Junk is to allow the user to check them in case a good email gets put there for various reasons and then they can select the email and state it is not junk, so helping to train the Junk Controls. Then any good emails stand out and are easily collected.

But yes, you have to consider that it is a valuable folder and actually look at it. I check on a daily basis and empty the junk. It is much easier and quicker to check a smaller list than wait for it to accumulate.

You can turn off Junk Controls. Tools > Account Settings > Junk Settings for the mail account or Menu icon > Options > Account Settings > Junk Settings for the mail account

uncheck 'Enable adaptive junk mail controls' If you never want your manual selection of Junk to go to account Junk folder. uncheck 'Move new junk messages to'

Click on 'Global Junk Preferences' button if you still want to be able to manually mark as junk, select 'when I mark messages as junk' If you wish you could select 'Delete them' instead of using the accounts Junk folder.

click on all OK's to close and save changes.

If you have all your mail going to eg :Inbox Make sure you create folders to organise your mail. It is advisable to keep the Inbox low in email numbers and use it as an Inbox for incoming mail and not as a general storage. Compact on a regular basis to remove all traces of marked as deleted emails.

Have fun :)

First off Thunderbird defaults to having no Junk folder. It just marks anything that it thinks is junk with an icon and places it in your Inbox. If you or someone else changed that the junk settings located in Account Settings.

From the menu Bar select Tools-Account Settings-Junk Settings

Go there an turn it off.

No menu bar? Press the alt key.

If you are complaining about messages ending up in your email provider Spam folder, complaint to them. Thunderbird has nothing to do with that.

I have nothing checked on the Junk page in settings but still random mail goes into the Junk folder and random mail goes into the Inbox. I don't need Big Brother deciding what I should read by using a flawed algorithm. I'm over 60 years old and I'm lucky I can remember to check one mailbox. I check the Junk whenever I remember but so far that has been monthly or less. I have just checked something down at the bottom of the Junk Settings page that says send all junk to Inbox so we'll see how that works.

Thank you both for your prompt and informative responses.