Try to start Windows in safe mode with networking enabled. - Win10 http://windows.microsoft.com/en-us/windows-10/change-startup-settings-in-windows-10#v1h=tab01 - Win8 http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-safe-mode# - Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

Still in Windows safe mode, start Thunderbird in safe mode. - https://support.mozilla.org/en-US/kb/safe-mode

Does the problem go away?

I did as you directed above; ver. 45 will ONLY display any messages will ALL add-ons disabled: Conversations, Startup Master, and Lightening.

But then it DOES NOT show a Unified Inbox, only an Inbox below each email account.

Any ideas?

Please confirm:

Did you start both, Windows and Thunderbird in safe mode as requested?

Or did you start Thunderbird only in safe mode?

When I started BOTH in Safemode, TB displayed the messages. I went into Autoruns.exe and disabled two little programs that I have added in the last 2 months and rebooted. No help. It still won't display the messages, but it does run Lightening 4.7 now! The only add-ons I have in TB are Lightning, Start-up Master (added at least 6 weeks ago), and TB Conversations which was added 9+ months ago.

Does that help? I cannot run both in Safemode all the time, needless to say.

Windows safe mode disables anti-virus software, which is most likely the culprit.

Create an exception in your anti-virus software for the Thunderbird profile folder, so that the anti-virus real-time scanner will not scan it. http://kb.mozillazine.org/Profile_folder_-_Thunderbird

Don't let your anti-virus software scan incoming and outgoing messages.

Don't let your anti-virus software scan attachments.

Don't let your anti-virus software intercept your secure connection to the server.

Remove any add-ons your anti-virus software may have installed in Thunderbird.

I have seen Conversations mentioned as causing problems with v45. Have you checked to see if you are on the lasted version of Conversations.

https://addons.mozilla.org/en-US/thunderbird/addon/gmail-conversation-view/

Interestingly enough, with the update to 45.1.0 I no longer have the problem.

Good. When version 45.1 fixed it, can you then mark the thread as 'Solved' please? Thank you.