Have you created a pop or imap mail account?

Pop mail account will auto delete off server when you download unless you selected to 'Leave messages on server'. In same location you could also select 'Until I delete them', which would remove deleted emails off server. Right click on pop mail account in folder Pane and select 'settings' select 'Server settings' to see relevant Account setting page.

Imap mail accounts see a virtual copy of what is on server. You subscribe to see folders on server. Right click on imap mail account in folder Pane and select 'Subscribe' select the server trash folder and click on 'Subscribe'. click on OK. You would subscribe to see the server 'Trash' folder which might be called 'Trash' or 'Bin' or other variants. Emails you put in the subscribed imap 'Trash' folder are also put in the 'Trash' folder on server. But you must select the server Trash folder in Account settings > Server Settings. Right click on imap mail account in folder Pane and select 'settings' select 'Server settings' to see relevant Account setting page.

In all instances, you would need to compact folders to fully remove hidden marked as deleted emails. You can set imap Inbox to compact/expunge each time you exit Thunderbird.

See example images below:

Thanks. I have pop mail account and I already tried the option you suggested (selecting: 'Until I delete them') before posting my question but unfortunately IT DOES NOT WORK. The messages DO NOT get removed from my inbox on the server after I delete them in Thunderbird. Any other ideas?

When you delete messages they are hidden and get 'marked as deleted', but at this point they still exist in Inbox. This facilitates recovery in case of accidental deletion. To fully remove the deleted emails, tidy mbox file and recover space, you need to compact the folder.

Right click on 'Inbox' folder and select 'Compact'. It is also worth doing the 'compact' on 'Drafts' and 'Junk' as well because those folders get a lot of emails deleted.

I am using the Polish Thunderbird and the word that is used there is "order" instead of "compact". I am assuming it is the same as I don't see anything else similar looking to compact when I right click on the inbox folder. Unfortunately when I tested it - deleted couple of messages, ordered/compacted inbox folder and checked my gmail account on the server, the messages are still there on gmail. So I am sorry to say but it is not working.

re :checked my gmail account on the server, the messages are still there on gmail. That explains a few things as gmail server and others that are following the gmail design have a few quirks that can effect pop mail accounts.

Gmail keeps all of its incoming and outgoing emails in the 'All Mail' folder. 'All Mail' is also gmails archive folder. To make emails look like they are in various folders which is what most people understand, gmail applies labels (a bit like tags) to emails in the 'All Mail' folder so they can show up in other folders like the Inbox. This method of labelling means one email can be shown in more than one folder and gmail can apply it's own labels so emails appear in eg: 'Important' folder as well.

When emails are deleted via Thunderbird one of two things can occur and to some extent this depends upon the type of mail account you use and also where a deleted email is placed. If you just delete the email and do not put it in the gmail trash folder, then only the label is deleted. This means the email still exists on the server in the original folder - 'All Mail' and any other folder gmail may have automatically displayed it in. Note it is possible to access the webmail account and make changes to settings to prevent gmail from auto putting mail in other folders. This effects both pop and imap mail accounts.

If the email is deleted and put into the gmail server 'Trash' folder which may also be called 'Bin', then gmail will automatically empty the 'Trash/Bin' folder approximately every 30 days. If the email was in the 'Trash' then it will get deleted from the 'All Mail' folder and it is properly deleted.

Imap mail accounts see a virtual copy of the server folders. You subscribe to see whatever server folders you want or need to see. Folders are synchronised so the copy in Thunderbird is the same as the server. Only imap mail accounts can delete an email from eg: Inbox or any other server folder they have subscribed to see and put it in the server 'Trash' folder because imap accounts have access to any server folder.

Pop accounts can only access and download from the server 'Inbox' and emails that are in the pop account Inbox can be deleted from Thunderbird, but upon compacting folder, gmail would only delete the 'Inbox' label because you cannot put the email in the gmail trash folder as you have no access to it. This means emails are not truely deleted from gmail server and would require periodic access to webmail account to properly delete those emails from the 'All Mail' folder.

Perhaps this explains what is going on in your case.

Thanks for your efforts to help me. I am pretty sure that someone with a little bit more patience or tech knowledge than I would make it work but it seems a little too complicated for me. I switched to Microsoft Mail Application that unlike Thundeebird seems to be deleting emails from gmail inbox just by deleting them in Mail Application. Thank you for now. Best regards, Rafal

Currently your selection of a trash folder for gmail is ignored. Look for Thunderbird 68.1 to be released very soon for a solution.

Post 68.1 you will need to restate the folder to be used for trash in account settings.

Bug 1579304 and it's predecessor Bug 1175446 refer https://bugzilla.mozilla.org/show_bug.cgi?id=1579304 https://bugzilla.mozilla.org/show_bug.cgi?id=1175446

Thank you for very much your reply. Does it mean that I have to unistall the Thunderbird I just installed? Or is there a way to reinstall the one that I have to 68.1 so I can keep all the email accounts and mails I already downloaded? I am not sure what you mean by "restate the folder to be used for trash in account settings". And I don't understand what I am supposed to do with links you sent me. Do you know or anyone knows an easier solution to this? I used to love Thundebird so much for its simplicity and now I am on a verge of just giving it up.

Matt: Those bugs seem to relate to 'Imap' Trash folder.

rafalacim has a POP mail account, so when rafalacim deletes email and compacts the folder, the email should only have the 'Inbox' label removed, but it is never going to delete the email from the 'All Mail' folder because pop accounts do not have access to the gmail Trash folder. But the issue is that the email is not having the Inbox label removed.

rafalacim: Account Settings for pop definately need the option (selecting: 'Until I delete them'). After selecting 'Until I delete them' , did you click on OK to save and close Account Settings and then restart Thunderbird to ensure the current session was using the updated setting?

When you delete emails, the email is shown in the Pop Trash folder. After a while you have several emails in the Trash. At this point emails still reside in pop mail account because you may need to recover them. Then you would 'empty Trash' folder and compact the 'Inbox' to fully remove emails.

This is the point when emails should get deleted out of server Inbox and gmail will remove Inbox label and archive the email in 'All Mail' folder on server.

Because you use POP, you will always need to access gmail's webmail via browser periodically to delete emails from the 'All Mail' folder to increase available quota. You will have to do that even when using the Mail Application.

Only after doing that emails should then get removed from server Inbox. Q: When you are deleteing the emails, are you deleting emails that are only in the Pop account 'Inbox' folder or are those emails in other folders or both? Q: In webmail do you have have Inbox emails in other categories like 'social' etc or have you adjusted webmail settings so that no Inbox emails appear in other Inbox categories?

Thank you for your message. I appreciate you giving me advice in simple not technical words I can understand. :) Yes, I always have the option "Until I delete them'. So far everyone was telling me that I have IMAP server, but after you said I have POP server I changed it in Thunderbird to: pop.gmail.com , port 995 I also changed it directly in gmail settings on the gmail server (from IMAP to POP, and switched off IMAP in gmail) Is that what I am supposed to do? Then I tried to delete the TEST messages directly from the Inbox (I don't have other "social" categories and the emails that I delete are only in the inbox folder) in Thunderbird, then from the Trash folder in Thundirbird, but that didn't affect the server. The deleted test message ARE STILL in the inbox folder in gmail.

re :So far everyone was telling me that I have IMAP server,

In earlier comments, I asked if you had pop or imap and provided two images showing the different types of account. In reponse you said: Thanks. I have pop mail account and I already tried the option you suggested (selecting: 'Until I delete them')

So, you provided that information.

Which is why I'm now a bit confused, because you have just said: So far everyone was telling me that I have IMAP server, but after you said I have POP server I changed it in Thunderbird to: pop.gmail.com , port 995.

You cannot simply change the server name to swap from pop to imap or imap to pop unless you had already done that before and are trying to rectify a mistake. Altering server names will cause all kinds of issues.

Right click on mail account name/email address in Folder Pane and select 'Settings' select 'Server Settings' to see relevant Account setting page. Please post an image of your Account Settings window and the forum can advise you on all the settings you should be using.

When I was saying that everyone was telling me I had IMAP server, I was reffering to other people I asked for advice including google support center. So I switched from pop to imap in Thunderbird, and then after your message I switched back to pop both in thunderbird and on gmail server. Misunderstanding, oh well. I had no idea it may cause any issues. Anyway, I appreciate your efforts to help me, but it is just too complicated for me. I just decided to uninstall Thunderbird from my computer. Maybe if find someone around that can fix it directly on my computer I will get back to it. Thank you for now. Best regards.