The best way to do what you want is to get copies of emails into the 'Local Folders' mail account.

If you want to move a load of emails, suggest you make sure your imap folders synchronise with server and download full copies of emails. Info here on selecting folders for full download:

• https://support.mozilla.org/en-US/kb/imap-synchronization#w_configuring-synchronization-and-disk-space-usage

Then go into 'offline' mode to stop folders synchronising whilst you do a load of moving. Menu icon > File > Offline > download/synch now select 'Work offline once download and/or sync is complete' click on OK

Then highlight batches of emails; right click on highlighted emails and select 'Copy to' and select a suitably named folder in 'Local Folders' mail account.

Once you have copied them, Delete them from the imap folder so they get moved into the subscribed gmail imap folder. Go back to online mode - click on 'Two black screen icon' in bottom status Bar. Compact the Inbox folder and any other folder which you deleted emails from and Empty the Gmail Trash folder. Gmail will delete emails that have been put into the gmail trash folder. This will free up space on server.

As loads of emails are now on your computer, suggest you backup the ...Roaming/'Thunderbird' folder located here: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\

Toad-Hall said

The best way to do what you want is to get copies of emails into the 'Local Folders' mail account. If you want to move a load of emails, suggest you make sure your imap folders synchronise with server and download full copies of emails. Info here on selecting folders for full download:

• https://support.mozilla.org/en-US/kb/imap-synchronization#w_configuring-synchronization-and-disk-space-usage

Then go into 'offline' mode to stop folders synchronising whilst you do a load of moving. Menu icon > File > Offline > download/synch now select 'Work offline once download and/or sync is complete' click on OK Then highlight batches of emails; right click on highlighted emails and select 'Copy to' and select a suitably named folder in 'Local Folders' mail account. Once you have copied them, Delete them from the imap folder so they get moved into the subscribed gmail imap folder. Go back to online mode - click on 'Two black screen icon' in bottom status Bar. Compact the Inbox folder and any other folder which you deleted emails from and Empty the Gmail Trash folder. Gmail will delete emails that have been put into the gmail trash folder. This will free up space on server. As loads of emails are now on your computer, suggest you backup the ...Roaming/'Thunderbird' folder located here: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\

Thanks for the answer. To be honest I'm looking for an easiest solution. I would like to archive emails in the local folder and, at the same time, delete them from gmail forever by pressing the "archive" button in the thunderbird interface. In my opinion the client should do this when in the account settings I choose to archive the messages in the local folder rather then in the gmail folder.

re : Archive - In my opinion the client should do this when in the account settings I choose to archive the messages in the local folder rather then in the gmail folder. I want to save my mails locally, and also I want that those mails disappear from my gmail account in order to not fill it (actually it's at 75% due to this situation).

Yes, you can make the setting in Account Settings > Copies & Folders, so you click on 'Archive' and those email copies downloaded on your computer get stored in the 'Local Folders' mail account in an Archive' folder, but because it is an 'Archive' instruction on emails in imap folders and the emails are stored on the server, gmail also gets this instruction. When you click on 'Archive' gmail perceives this as meaning remove all labels, so only store the email in the original 'All Mail' folder - gmail uses 'All Mail' as it's archive folder.

Gmail only deletes emails that have been put into the gmail trash bin. Archiving is not a delete action and does not put emails in the Trash.

As you specifically asked that those emails get deleted off the server and not stored in the 'All Mail' folder so you can reduce your quota, I offered instructions to ensure that deletion.

If you use the setting in Account Settings > Copies & Folders, so you click on 'Archive' and those email copies downloaded on your computer get stored in the 'Local Folders' mail account in an Archive' folder, then you would still need to then access 'All Mail' either by subscribing to see folder or access via webmail account, locate all those 'archived' emails and manually delete to put them in the gmail Trash.

Gmail does not exactly make things so easy as one would necessarilly like. I understand your frustration with this because I also have an imap gmail account.