Ah...the All Mail messages reduced from 4,000 down to 100 after I allowed "compaction" to run. I'm horrified to learn what compaction now means (= delete). I've turned off "Compact folders if savings greater than 20mb". Hopefully that will stop me getting compaction invitations.

Possible solution: With the 4,000 messages still shown in (native) Gmail I could cut and paste all 4,000 All Mail Gmails into the (native) Gmail Inbox.

Then when I go back to Thunderbird the 4,000 Gmails will show in Inbox. Then I can move the 4,000 Gmails in Inbox to All Mails. This will be a real PITA (40 x 100 operations) but I think it will work. Then make sure I never use compaction again.

Does this sound OK  ?

Problem solved - well kind of:

1. Using (native) Gmail, I copied all 4,000 Gmails from All Mail to Inbox in one Bulk action
2. Using Thunderbird I then went to the Inbox which, as a result of the above action, had grown by 4,000 Gmails.
3. Using Thunderbird, I then set up a new folder called "ALL MAIL - manual". This went directly under Thunderbird Inbox (not a "Local folder").
4. I then copied the whole of my expanded Thunderbird Inbox to (1) "All Mail - manual" and (2) to a Local Folder (stored in a Thunderbird sub folder on my hard drive).
5. I now have all emails I want and can access them easily. I also have a hard disc backup of them all.
6. I cannot be certain, but I think allowing the innocuous sounding "do you wish to compact the folder" was a factor.

Do not subscribe to All Mail

ALL MAIL is Gmails way of storing ALL mails in one single container. Then Gmail marks/flags mail to be show in this or that box. The mails DOESN'T EXIST in those boxes. The container also includes mails MARKED as deleted and spam.

When you deletes a mail in a TB-box it is first COPIED to the trash-box then marked (as to be) deleted in its original box. Mails in TB is kept in one single file for every box If you have 4000 mails in one box ... that could be one very large file. As mails are stored one after another it is not possible to erase one mail within this file. Therefor the "to be deleted" -mark is set (Also easier to undelete)

Compacting is to rewright this file without those mails and delete the old file

Subscibing to All Mail and Inbox just make you download the same email twice

Gnospen,

Thank you for the time you took to consider my issue. I am grateful. I accept you are considerably more knowledgeable than I.

My problem was I wanted to see all the emails I'd ever sent or received and which I hadn't got rid of permanently. I won't say "deleted" here because - like "folders " and "compaction" - that words means different things to different folks.

I also wanted to have an off line backup copy of all emails on my hard disc. The combination of the two processes would reduce the risk of losing any important emails. Mailbird would do most of this, but given my advancing years, I found the pale gray font less eye-friendly than Thunderbird's sharp, clear Inbox layout.

After much investigation and multiple postings, I've achieved what I wanted to do. Sure it's not elegant and there is duplication. If I never use compaction maybe I won't need to repeat the process.

But if you have a better idea how to meet my objectives I;d genuinely be pleased to learn from you.

I can tell you how I do

• I move most of my mail to folders under Local Folders
• I only keep mail for the last days in INBOX then with a filter I move all mail older than 4 days to a temp-inbox under Local Folders
• I compact regulary and have INBOX set to "expunge" on exit.
• Every year I "Archive" the mail
• I have "ImportExportTools" installed and set to take backups every 3 day to another disk (microSD) IET is set to only backup changed files. Thou I ones in a while let IET take a full backup Just to make it easier to restore if I need to.

This way I have most of the mails in folders (files) that are very seldom change (so they will not be backup'd all the time) and the others are small and therefor easy to backup.

Thank you. It's much appreciated.