How to restore all inbox data after obliged to create new mail account

Question

After my Thunderbird account mysteriously disappeared I had to re-open another mail account. After difficulty I restored address book. But only about 30 percent of email inbox restored. How can I restore the rest, many of which were important to me.

Answer 1

'''Background info to help you understand your mail account:'''
As you saw in the Profile folder mail accounts, 'folders' you see in the Thunderbird FolderPane are actually Files; mbox files.
Emails are downloaded to your Inbox and stored one after the other in the order they were downloaded. So, the emails are not stored as individual files, they are written into a text file which can get bigger and bigger if you do not manage the Inbox.
Any emails you delete, from your point of view they disappear from Inbox and reappear in 'Deleted' folder (Also called Trash).
In reality, those deleted emails are 'marked as deleted' and are still in the Inbox, but hidden. This means that if you had accidentally deleted an email, it would be easy to quickly get it back.
However, the deleted emails are still taking up space, so to clean up the file and remove those 'marked as deleted' emails, you have to 'compact' the folder. If you do not compact your folders then you increase the possibilty of getting a corrupted file and losing emails.
Using folders to organise emails into groups keeps the file size smaller and makes it easier to locate emails. It is also less risky. Smaller files also use less memory to open.
'''How to create Folders:'''
Select the mail account name in the Folder Pane. If you want to create them in 'Local Folders' account, select 'Local Folders'.
* 'File' > 'New' > 'Folder'.
* Give folder a name eg: Bills or Family or Friends etc
* click on 'Create Folder' button.
you can create as many folders as you need.
'''How to move emails from one folder to another:'''
There are a couple of ways to this, so you could try out the methods and choose the one you find most comfortable.
Suggest you move one email first and then try to move a group.
'''1. Using right click options.'''
* Right click on highlighted/selected email in list
* select: 'Move to' > mail account / Local Folder > select name of folder
'''2. Using toolbar: '''
* Select email in list so it is highlighted
* 'Message' > 'Move to' > mail account > select: Folder'
'''3. Drag and Drop method'''
* Left click and keep down on hilighted email in list to grab
* Move the mouse pointer to hover over the Folder you want; this is dragging the email,
* Release the mouse to drop the email into that folder.
'''How to highlight several emails:'''
All the above methods work if you select one email or a highlighted group.
'''To select a batch of email eg: 10 adjacent emails'''
* click on first email
* Press 'Shift' key and click on eg:10th email - all emails in between become highlighted.
'''To select various emails to put them as a group.'''
* Hold down 'Ctrl' key and use mouse to select various emails.
'''To select all emails in folder:'''
* click on first email in list
* Hold down 'Ctrl' key and press 'A' - All emails will be highlighted.