Thunderbird has taken to asking my permission to purge all my deleted emails. I don't want to do that.

Yes you do. You just apparently do not understand what the issue involves. but you do want to compact.

See https://support.mozilla.org/en-US/kb/compacting-folders#w_why-is-compaction-required

The article is old, and the folder size limits no longer apply. But the fundamental reasons you needs to do it of reducing the chance of loosing data has not changed. You do want to do it. If you use IMAP you even more so want to do it.

I understand compacting. I compact. I am now being asked to permanently DELETE all deleted emails. There have been occasions when I've deleted emails accidentally. Blanket deletion therefore doesn't suit my purposes. I prefer to do some curated purging.

My question was about interpretation of Thunderbird's dialogue. The 'Proceed' button is ambiguous. I need to know whether it means 'proceed to delete everything' or 'proceed without deleting everything.' Can anyone tell me?

Better still, is there a way to stop this dialogue tripping me up every time I delete an email?

See https://support.mozilla.org/en-US/questions/1317882

I keep being told that I don't understand why I should delete all my deleted emails.

I think that in a backhanded way this is giving me an answer to my question. I think that I am being indirectly told that 'Proceed' means 'Proceed to delete all my deleted emails,' which of course I don't want to do.

If someone would be kind enough to confirm this for me this correspondence can close.

It will not be necessary to tell me again that I don't know what's good for me. I've understood that. I hope this is helpful.

Of course I would like to think that someone will eventually give me a simple 'stop asking me this every time' option.

Recently, the wording in that pop up was altered, it is now more geek speak and something developers understand, but they have failed to understand it is ambiguous to users who are more fully conversant with the word 'compact' as it has been used for donkeys years.

You are not alone in feeling wary and not really understanding what that popup really means. The wording does not correspond to any of the 'compacting' help articles nor the section in Options that relates to compacting to save X amount of space. It really does sound like it is about to Empty the Trash.

'Proceed' button means to proceed with the 'purge' aka 'compact' of files to clean them up, save space and reduce the risk of file corruption. If you alter the setting in Options that basically switches this off, then you really should perform compacting manually on a regular basis particulary on Inbox, Drafts and Junk.

However, you say "I understand compacting. I compact. ", so it seems surprising to see a prompt. Do you also compact 'Drafts' and 'Junk' ? If no, then these files could larger than expected with loads of deleted emails and therefore be prompting the pop up.

Info for anyone reading this: https://support.mozilla.org/en-US/kb/compacting-folders

Disk space settings:

• Menu app icon > Options
• select 'General'
• scroll to 'Network & Dik Space' section

Under 'Disk space' To set up auto compact :

• Select checkbox 'compact all folders when it will save over X MB in total'

This will then offer the prompt to compact folders to save space - this is that ambiguous message about purging deleted emails - note that pop up message does not say 'Empty Trash'. Uncheck that option to switch it off, but be mindfull to frequently compact all your folders and not just the Inbox.

Better still, is there a way to stop this dialogue tripping me up every time I delete an email?

Compact the folder. Despite anything else it is compacting the dialog is talking about.