So you do not mark messages as junk and they move to deleted, you never move mails from the inbox to another folder. That sounds like an accident waiting to happen. But each to their own.

As compacting does not remove an mail that is visible in any folder, just do it.

To be fair, I didn't understand exactly what you are trying to say Matt...!

I want to see which messages has been marked as deleted because (maybe, by accident) I deleted them without intending to do so... (for example, maybe I moved a folder to trash, out of sheer momentum by my mouse...).

How can I see (and maybe restore) these e-mails instead of totally deleting/compact them?

Anyone who has an answer?

I would like to see the list of messages that has been marked as deleted by Thunderbird to see what went wrong (maybe I moved by mistake some messages to Trash for example sometime...).

There is no reliable way to see all messages that will be affected by compact - because it includes messages that have been moved (manually or automatically by Junk filter for example), deleted, and also automatically purged by retention.

The best you can do is look at trash folder. If all your manually deleted messages are in trash, why not just check trash?

@Wayne Mery,

the problem is that I have nothing in Trash!! The Trash folder is empty. And Thunderbird wants to delete over 200MB of data! So I am not sure if it will delete (by bug or by accident) important data or junk as you say...

Since all e-mails for a specific account are stored in only 1 file in Thunderbird, and the e-mails for compacting are just marked as deleted and they continues to exist in this file, how hard is someone to read only the records of the file that has for example a "deleted=1" field?

how hard is someone to read only the records of the file that has for example a "deleted=1" field?

Until you can figure out why messages are not in the Trash folder, the best you can do in that respect is change account settings for "When I delete a message" to "Just mark it as deleted".

the best you can do in that respect is change account settings for "When I delete a message" to "Just mark it as deleted".

Wayne Mery, until we find a way to read these messages, can you please tell me where this setting is located? Because I can not find it.

Account Settings > (pick your account) > Server Settings

Then for messages which have been deleted, you will see them in the message list with strike out through the line.

It is probably only applicable to messages you delete AFTER you change the setting. So it won't help you with messages you already deleted.

Account Settings > (pick your account) > Server Settings

Wayne Mery, did you see the screenshot in my previous answer??

Sorry, I was thinking you have an imap account, but you have a pop account.

• Right click trash folder and pick properties. What is the "file size on disk"?
• Does https://support.mozilla.org/en-US/questions/1082151 help?

@Wayne Mery, the problem is that I have nothing in Trash!! The Trash folder is empty. And Thunderbird wants to delete over 200MB of data! So I am not sure if it will delete (by bug or by accident) important data or junk as you say... Since all e-mails for a specific account are stored in only 1 file in Thunderbird, and the e-mails for compacting are just marked as deleted and they continues to exist in this file, how hard is someone to read only the records of the file that has for example a "deleted=1" field?

Seriously, that is not correct. It is one file per folder, not one file per account.

The files are text files, so you are welcome toopen the file is a text editor and laboriously check through the contents of the file looking for messages with a x-mozilla status of 08. I slow process, but apparently you are stuck on a small and irrelevant point the amount of space it claims will be saved. It is a known fact that the disk space reported that will be saved is often incorrect. You may well compact and save nothing. Like I said right at the beginning, just do it. (compact)