Additional information: I am able to send email from the other comcast emails I have. It's just the one that wants to log on with a non-existent username, and of course, the inability to see the setting on any of the email accounts.

Currently the account: [email 1]@comcast.net is set up to use a different email address when sending.

First you need to see if you have an outgoing server SMTP) that is set up for [email 1]@comcast.net.

Menu app icon > Account Settings Scroll down so you can see 'Outgoing server (SMTP)' in the left pane. Click on 'Outgoing server (SMTP)' - see image below as guide. It will show you a list of outgoing smtp servers.

However, it sounds as if you cannot get that far. re: When I go to account settings to check the outgoing SMTP all I get is the option to add or delete an account. Do you get any other error message like an account with that name already exists etc ?

What version of Thunderbird are you using? What OS Windows, Mac, Linux ?

Try this:

• Help > Troubleshooting Information
• Under Application basics '
• 'Profile Folder' : click on 'Open Folder' or 'Open Finder'

A new window opens showing the contents of your profile name folder.

• Exit Thunderbird now.- this is important.

• Scroll down you will see a 'prefs.js' file.

Do you see other similar named files eg: 'prefs-1.js', 'prefs-2.js', 'prefs-3.js' etc ? If yes:

• Delete any of those 'prefs-n.js' files that have a zero size.

If the last one with biggest number is eg: 'prefs10.js'

• Rename 'prefs.js' to say 'prefs-11.js'

• Rename eg: 'prefs-1.js' to say 'prefs.js'

Then restart Thunderbird.

Did this work ?

Thank you. I am now able to send email from email1@comcast.net but still have the issue with no access to settings on all my email accounts.

Current Windows 10 10.0.18363 Firefox 80.0(64 bit) Thunderbird (68.12.0 (32bit)

When going to View Setting on the Account I only get the options to add, delete or set as default. No error messages. I'm reluctant to try set as default as I don't know what that will actually do.

Following your directions, I had prefs-1.js through prefs-8.js. After deleting those with a zero size I was left with prefs-5,6 and 8.js. I renamed prefs.js to 9 and prefs-5.js to prefs.js. Restarted Tbird and it now asks for a password for email3@comcast.net which is active and which I knew but is not the email I was sending from.

The profile name folder currently shows prefs.js, prefs-6.js, prefs-8.js and prefs-9.js. If this means there are only three profiles set up I am missing something as I actually have four comcast emails in use and 2 with another domain.

So, now I need to know how to get to the settings for each email account.