So the old mail account is a POP mail account.

What is the new hosting account, will you be using IMAP or POP ?

If the new hosting is going to use only POP: As emails are downloaded from server Inbox to your Thunderbird POP mail account Inbox and there is no synchronising of folders as seen in imap mail accounts, you can simply update your Account Settings.

'Tools' > 'Account Settings' > 'Server Settings' for pop mail account or right click on mail account name in Folder pane and select ; Settings then 'Server Settings' for pop mail account

• modify/edit 'Server Name'
• If using port 110
• Connection Security = none
• Authentication method = Password

• If using port 995
• Connection Security = SSL/TLS
• Authentication method = Normal Password

Select 'Outgoing Server (SMTP)' in left Pane.

• select the outgoing server in list
• click on 'Edit'

Modify/edit

• 'Server Name'
• Port : 465
• Connection Security: SSL/TLS
• Authentication method = Normal Password
• click on ok

Make sure the pop mail account has the updated server applied.

• select account name in left pane.
• Bottom right - Outgoing Server (SMTP) - select the correct server

When finsihed click on OK.

Remove old passwords. Tools > Options > Security > Passwords tab

• Click on 'Saved Passwords'
• click on 'Show passwords'
• Select both mailbox and smtp account
• click on 'Remove'
• click on Close'
• Click on OK

Close and restart Thunderbird. At the prompt enter password and select to remember password.

If the new hosting is going to use IMAP: create a new mail account File > New > Existing Mail account or Menu icon > New Messages > Exisitng mail account

Enter your name, email address and password (password you use to access the new hosting webmail) click on 'Continue' Thunderbird will try to configure settings, but you may need to click on 'Manual config' button to enter correct settings - making sure you have selected IMAP click on 'Done' to create a new imap account.

The old pop account can remain where it is but stop it searching for/downloading new mail in Account Settings > Server Settings OR you can move all the emails into suitably named folders in the 'Local Folders' mail acount and then remove the old pop mail account.

BillEdit515 said

My current (business) email address is MyName@MyCompany.Co.Uk previously registered with an ISP using pop3.IspAddress (port 110) and smtp.IspAddress. My new ISP informed me that the outgoing and incoming servers are both mail.MyCompany.Co.Uk the outgoing server using authentication. How do I substitute the new ISP's servers for the old ISP's servers when configuring TB to use these new settings (servers)? Everything else stays the same.

Many thanks - that has solved my problem (I'm continuing to use POP3 on Port 110) . I've connected to my new ISP and it reported 'no messages' (exactly as I expected).

I'm not sure if Toad Hall received my grateful thanks. This solution is exactly what I needed - worked perfectly. Still using POP3 on Port 110 (and Mozilla Thunderbird found my servers automatically - quite brilliant). Many thanks.

Good to hear all is ok for you.