Deleting an email from the server automatically deletes it from Thunderbird
My email accounts are provided by Utility Warehouse. I use Thunderbird to download my emails from the UW club server and store them on my PC. Space on the server is limited and so I have to delete emails from the server on a regular basis. At one time if I deleted an email from the server it remained safely in my Thunderbird Inbox on my PC but something must have changed recently so that if I delete emails from the server they are also deleted from my PC. Sometimes they are moved to the Deleted folder, sometimes to the Trash and sometimes they seem to be removed completely. There doesn't seem to be any settings I can find on the server which relate to this, and in Thunderbird I can't find any settings that might cause this. The PC seems to be synced precisely with the server when I don't want it to be. If I empty the Deleted folder on the server it empties it on the PC as well. Any suggestions welcome.
ప్రత్యుత్తరాలన్నీ (1)
As per your description this sounds like an IMAP account. Is it? Then the behavior is how IMAP works.
In order to preserve space on the server, you'd need to copy messages from the server to your Local Folders account prior to deleting those messages on the server.