My suggestion is to revisit your decision to keep the AllMail folder, since it is a duplicate of other message folders.

In inbox i receive duplicate emails, keep comings, and keeps coming and email.......

The 'allmail' folder will always be duplicates.

To reduce your space usage,

1. in Thunderbird you will need to unsubscribe from the All Mail folder, 2. with Thunderbird shut down, delete the All Mail file and All Mail.msf file in the account's folder which you can find at Server Settings | <account name> | Server settings | local folder

For example /Users/me/Library/Thunderbird/Profiles/xxx.default-beta/ImapMail/imap.gmail-4.com/[Gmail].sbd

The account its not IMAP, i use POP3.

THe problem is likely your 'allmail' folder. It contains duplicates. you can unsubscribe from it at accounts>subscribe panel. Once that is done, you can delete the folder.

The account its not IMAP, i use POP3.

Your previous screen shot suggests that you are using imap, so we need more information.

Please post only the top section of Help > Troubleshoot information showing your accounts. Please post a screen shot of the left side of Thunderbird showing all the accounts and folders. In your pop account(s) (account settings > server settings), is "leave messages on server" unchecked?

Sorry for screenshot it was that i find in Google, bcs i didn't make one. About the "leave messages on server", the tick is checked. The strange thing is that, duplicated emails are with attachment around 15-20MB.

About the "leave messages on server", the tick is checked. The strange thing is that, duplicated emails are with attachment around 15-20MB.

This is likely part of the problem. I suggest you uncheck it, and all other pop space saving features.

When using pop, you really shouldn't be keeping messages on the server. Also, deleting popstate will cause messages to be redownloaded.

> i receive duplicate email , if duplicate happens i need to delete message in my hosting company(through webmail client) after that i need to delete all duplicate emails, all duplicate emails are with attachments(different .doc, .pdf and etc.)

Who is your mail provider / hosting company? And is there no pattern to getting duplicate messages that you see in webmail?

Also, ...

IMO maildir is not a space saving feature. But that there is no going back.

And if you are short on disk, suggest you use something like windirstat or treesizefree to find which directories are using the most space.

> I don`t have any limits in shared drive

If you are using a file share / networked disk, this is also unfortunately another potential source of problems - there can be Thunderbird bugs. If you are able, I suggest you move your Thunderbird profile back to local disk. How much available space is on your disk?

There is no way to move Thunderbird profile in local disk for now.I have few TB free of space, definitely free space is not a issue. I will try with uncheck the tick for "Leaving messages on server". In webmail i don`t have any duplicated emails.I think issue is with TB, fileshare or both, specialty communication with TB and SMB, like you say maybe there are some bugs, but i`m trying to find them and find way to bypass them.

You won't be able to bypass SMB issues with any thunderbird settings, so I suggest don't bother looking for tweaks.

You need highly performant file shares for this to work well. Along those lines, if you are on Windows, make absolutely certain that AV software is not monitoring or scanning the Thunderbird profile directory, and the Thunderbird executable is also excluded.

Thank you for advice. I also think it is in SMB performance.

Another factor is folder size. Small folders will have less trouble in the file share environment. So consider moving messages out of your Inbox.