Update changed all server settings
Just a comment about glitchy updates: Running TB with 28 email accounts, 17 business, and 11 of those business prefer to keep their emails on the server for a month (two of them) and forever (the other nine). Recent update removed the checked box on server settings "Leave messages on server" which allowed TB to download and remove all messages from their servers (emails covered over two years).
Alla svar (3)
re :checked box on server settings "Leave messages on server" This option is only available for Pop mail accounts. If using Imap then all emails are stored on server so that option would not be available.
Well, if I'd known that bit of info before, this wouldn't have happened... I guess. However, since I've used the POP3 for about eight years without this update problem, I'd have to say... "darn it all, but life goes on." I have changed over to IMAP on all those accounts.
General info for anyone reading this.
Pop was easy to grasp and I like it's simplicity. You could only access and download emails from server Inbox, so you did have to check on the webmail account every once in a while. You could choose to auto delete off server on download or leave permanently or set a delay for a delete. So it managed the amount of space used on server. All emails were downloaded and stored on computer. There was no synchronising of folders. All emails could be read in offline mode and even if you accidentally removed a pop account, all the downloaded emails would still be lurking in profile just in case you removed the account in error. Life was simple.
Imap is like a virtual view of folders on server which you subscribe to see. Emails can be fully downloaded or only headers and this can vary depending upon the folder. Anything you do will effect what is on the server. Other access to server via eg: different computer, phone will effect the server and hence will effect what you see in Thunderbird. So deleting an email via phone connected to server will remove that same email from Thunderbird imap account when it connects with server. Because imap folders synchronise with server you cannot rely on them as a backup.
You can download full copies of emails and get copies out of the imap account into 'Local Folders' mail account. This means you can use 'Local Folders' to store emails as a copy in addition to the server or if you need to release space on the server but need to keep copy of email. Backups are still advised even if using an imap account.