You can easily remove Lightning via the Add-on Manager if you don't need it.

When there is no problem in safe mode, enable add-ons one by one until the problem occurs again.

Add ons manager is inactive in safe mode. TB will not run unless in safe mode.

I did remove Lightening (I think) via the safe start process. However, since the add ons manager is disabled, I don't now how to verify.

Add-on manager is not inactive in safe mode. Add-ons are not activated but you can remove, disable or enable (they show there settings at normal mode) Unless you checked to make those changes permanent. (don't do that)

There are no add-on entries showing..

I seem to recall that there were two in the beginning, but I selected to disable all permanently as I didn't really want either.

I also checked the plug-ins, and all were set to 'never activate'.

Thanks!

I seem to recall that there were two in the beginning, but I selected to disable all permanently as I didn't really want either.

Why did you complain about Lightning then? if it's not there then it didn't get installed in the first place.

I did remove Lightening (I think) via the safe start process.

If you're talking about safe mode, that doesn't remove add-ons, it just disables them.

What is your anti-virus software?

Yes, Lightening was installed and appeared to be running. I could see the calendar displays. Lightening and the other add on was disabled as desired but a restart of TB still hung. Not clear when the add ons were removed or what I did to effect the removal. I've never had any control when not in safe mode, so whatever I did was in safe mode.

I'm using Microsoft Security Essentials. The TB folder is in the exclude list as suggested.

I should add the Lightening install was a complete surprise to me. Later, I am going to ask how to prevent such surprises in the future.

Lightning add-on was bundle with this release. BUT it only displayed a bar at the bottom of TB offering you to install or not. I declined and it was NOT installed. Completely gone. That's what I call a proper bundle not like Flashplayer lures you into McFee.

So if it was installed you must have authorized it.

Only way to prevent this from happening again is: Don't update. Just like chat which I didn't ask for, it might become part of TB.

(I have thou changed my mind and installed Lightning)

Your problem: Does it work at all in safe mode?

Yes - every thing works fine in safe mode.

I don't recall seeing such a bar. I highly doubt I would have authorized it as I don't really need such a product. I feel pretty strongly that I did not authorize unless it was by sheer accident. But my memory is not the best and never was :-)

So, are you suggesting that my best recourse might be to uninstall TB and load a fresh copy?

Can you post your Troubleshooting Information? Help (Alt-H) - Troubleshooting Information

The info is too large to send in one piece. Part 1/2

 Application Basics

   Name: Thunderbird
   Version: 38.1.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Thunderbird/38.1.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150707103124
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3)  :110, plain, passwordCleartext
     OUTGOING: mail.hal-pc.org:2025, plain, passwordCleartext, true

   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account3:
     INCOMING: account3, , (pop3) 127.0.0.1:110, plain, passwordCleartext
     OUTGOING: 127.0.0.1:25, plain, none, true

   account4:
     INCOMING: account4, , (pop3) 127.0.0.1:110, plain, passwordCleartext
     OUTGOING: mail.hal-pc.org:2025, plain, passwordCleartext, true

   account6:
     INCOMING: account6, , (pop3) mail.hal-pc.org:110, plain, passwordCleartext
     OUTGOING: mail.hal-pc.org:2025, plain, passwordCleartext, true

   account8:
     INCOMING: account8, , (pop3) mail.hal-pc.org:110, plain, passwordCleartext
     OUTGOING: smtp.hal-pc.org:2025, alwaysSTARTTLS, passwordCleartext, true

   account9:
     INCOMING: account9, , (pop3) pop.googlemail.com:995, SSL, passwordCleartext
     OUTGOING: smtp.googlemail.com:465, SSL, passwordCleartext, true

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-9aa2bd52-59ff-470c-9d5b-195332140703 (7/2/2014)

 Extensions

Part 2/2

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 0
     browser.cache.disk.smart_size.enabled: false
     browser.cache.disk.smart_size.first_run: false
     browser.display.screen_resolution: 96
     extensions.lastAppVersion: 38.1.0
     font.internaluseonly.changed: false
     font.name.monospace.el: Consolas
     font.name.monospace.tr: Consolas
     font.name.monospace.x-baltic: Consolas
     font.name.monospace.x-central-euro: Consolas
     font.name.monospace.x-cyrillic: Consolas
     font.name.monospace.x-unicode: Consolas
     font.name.monospace.x-western: Consolas
     font.name.sans-serif.el: Calibri
     font.name.sans-serif.tr: Calibri
     font.name.sans-serif.x-baltic: Calibri
     font.name.sans-serif.x-central-euro: Calibri
     font.name.sans-serif.x-cyrillic: Calibri
     font.name.sans-serif.x-unicode: Calibri
     font.name.sans-serif.x-western: Calibri
     font.name.serif.el: Cambria
     font.name.serif.tr: Cambria
     font.name.serif.x-baltic: Cambria
     font.name.serif.x-central-euro: Cambria
     font.name.serif.x-cyrillic: Cambria
     font.name.serif.x-unicode: Cambria
     font.name.serif.x-western: Cambria
     font.size.fixed.el: 14
     font.size.fixed.tr: 14
     font.size.fixed.x-baltic: 14
     font.size.fixed.x-central-euro: 14
     font.size.fixed.x-cyrillic: 14
     font.size.fixed.x-unicode: 14
     font.size.fixed.x-western: 14
     font.size.variable.el: 17
     font.size.variable.tr: 17
     font.size.variable.x-baltic: 17
     font.size.variable.x-central-euro: 17
     font.size.variable.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     mail.openMessageBehavior.version: 1
     mail.winsearch.enable: false
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 6d26d9c3-e16f-4e80-87b7-9944c4a03c2
     mailnews.database.global.indexer.enabled: false
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1437590897
     places.history.expiration.transient_current_max_pages: 79857
     places.history.expiration.transient_optimal_database_size: 82696436
     plugin.importedState: true
     plugin.state.flash: 0
     print.print_printer: Lexmark 5600-6600 Series (Network)
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_bgcolor: false
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_bgimages: false
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_colorspace:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_command:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_downloadfonts: false
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_duplex: -2121269117
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_edge_bottom: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_edge_left: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_edge_right: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_edge_top: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_evenpages: true
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_footercenter:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_footerleft: &PT
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_footerright: &D
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_headercenter:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_headerleft: &T
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_headerright: &U
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_in_color: true
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_margin_bottom: 0.5
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_margin_left: 0.5
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_margin_right: 0.5
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_margin_top: 0.5
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_oddpages: true
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_orientation: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_page_delay: 50
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_data: 1
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_height: 11.00
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_name:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_size_type: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_size_unit: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_paper_width: 8.50
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_plex_name:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_resolution: -2113404921
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_resolution_name:
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_reversed: false
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_scaling: 1.00
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_shrink_to_fit: true
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_to_file: false
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_unwriteable_margin_bottom: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_unwriteable_margin_left: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_unwriteable_margin_right: 0
     print.printer_\\DELL\Lexmark_5600-6600_Series_(Network).print_unwriteable_margin_top: 0
     print.printer_\\hamshack\Canon_i450.print_bgcolor: false
     print.printer_\\hamshack\Canon_i450.print_bgimages: false
     print.printer_\\hamshack\Canon_i450.print_command:
     print.printer_\\hamshack\Canon_i450.print_downloadfonts: false
     print.printer_\\hamshack\Canon_i450.print_evenpages: true
     print.printer_\\hamshack\Canon_i450.print_footercenter:
     print.printer_\\hamshack\Canon_i450.print_footerleft: &PT
     print.printer_\\hamshack\Canon_i450.print_footerright: &D
     print.printer_\\hamshack\Canon_i450.print_headercenter:
     print.printer_\\hamshack\Canon_i450.print_headerleft: &T
     print.printer_\\hamshack\Canon_i450.print_headerright: &U
     print.printer_\\hamshack\Canon_i450.print_in_color: true
     print.printer_\\hamshack\Canon_i450.print_margin_bottom: 0.5
     print.printer_\\hamshack\Canon_i450.print_margin_left: 0.5
     print.printer_\\hamshack\Canon_i450.print_margin_right: 0.5
     print.printer_\\hamshack\Canon_i450.print_margin_top: 0.5
     print.printer_\\hamshack\Canon_i450.print_oddpages: true
     print.printer_\\hamshack\Canon_i450.print_orientation: 0
     print.printer_\\hamshack\Canon_i450.print_pagedelay: 500
     print.printer_\\hamshack\Canon_i450.print_paper_data: 1
     print.printer_\\hamshack\Canon_i450.print_paper_height: 11.00
     print.printer_\\hamshack\Canon_i450.print_paper_size: 6553714
     print.printer_\\hamshack\Canon_i450.print_paper_size_type: 0
     print.printer_\\hamshack\Canon_i450.print_paper_size_unit: 0
     print.printer_\\hamshack\Canon_i450.print_paper_width: 8.50
     print.printer_\\hamshack\Canon_i450.print_reversed: false
     print.printer_\\hamshack\Canon_i450.print_scaling: 1.00
     print.printer_\\hamshack\Canon_i450.print_shrink_to_fit: true
     print.printer_\\hamshack\Canon_i450.print_to_file: false
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_bgcolor: false
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_bgimages: false
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_command:
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_downloadfonts: false
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_evenpages: true
     print.printer_Auto_Epson_Stylus_Photo_700_ESC/P_2_on_SERVER2.print_footercenter

According to your Troubleshooting Information there are no extensions installed. I still don't understand what exactly you did, extensions do not mysteriously disappear by starting Thunderbird in safe mode. So I guess there is something you haven't mentioned yet. With no extensions installed Thunderbird should work just fine in normal mode.

You still haven't answered the question what anti-virus software you use.

I have posted that twice now. Once in my original post and again in response to your anti virus question:

Microsoft Security essentials (auto update on).

When I started in safe mode, I specified to permanently disable add ons. That apparently caused the extensions to be removed.

I agree that TB should work just fine, but it doesn't. It could be that the add on is a red herring and there is something else in the update package causing the hang. I also note that there has been a flurry of updates from Microsoft, to include some to Microsoft Security Essentials.

I have posted that twice now. Once in my original post and again in response to your anti virus question:

Apologies, I've missed that.

Try to start *Windows* in safe mode with networking enabled.

- Win8 http://windows.microsoft.com/en-US/windows-8/windows-startup-settings-including-safe-mode

- Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode

- XP http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx

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 will do as you ask, but I don't see the point of starting both Windows and TB in safe mode. As I posted, TB works fine in safe mode.

I suppose I could try starting Windows in safe mode and TB in regular mode. Is that what you are really asking?

Good point, that would make more sense. The idea is to determine if your anti-virus software is causing the problem. Windows safe mode disables anti-virus software.

Ok, Windows started in safe mode and TB started normally and seems to be working fine.

As you suggest, that seems to point to the antivirus or to a recent Windows update.

I'm really uncomfortable running without my antimalware running, so I'm switching back to Windows regular mode.

Tell your anti-virus software not to scan the Thunderbird profile folder. Don't let it scan incoming and outgoing messages. And don't let it scan attachments.

No joy. I tried to attach a screen shot of the exclusion list, but I couldn't figure out how to get a file type that this app would accept. And, of course, I couldn't simply copy/paste the list.

Remember, all was working just fine up until that last TB update.

I now have a good workaround:

TOOLS>OPTIONS>ADVANCED clear USE HARDWARE ACCELERATION

TB is now WAD. TB starts and runs normally in regular mode.

Thanks for all your help.

I didn't close this thread as solved because you might want to work on that hardware acceleration issue.