sorry meant to say TB 45.4 - that is my current version

how can I export my emails from TB so that i can load them into a new email program?

Thunderbird uses the mbox format for mail storage. The files are plain text, so there really is no need to export anything. Once you picked a new email software find out how that can import from mbox files.

please don't ask me to troubleshoot

I'd have had a suggestion, but since you're not interested I skip that.

Thanks. If the suggestion is simple I'll give it a go

BTW having opened the program once it now refuses to open at all unless I reboot the computer.

Try to start Thunderbird in safe mode. https://support.mozilla.org/kb/safe-mode-thunderbird

Also, please post your Troubleshooting Information. At the top right of the Thunderbird window, click the menu button , then select Help > Troubleshooting Information. Press the Copy text to clipboard button and paste the information into your reply.

Here is what it provided

 Application Basics

   Name: Thunderbird
   Version: 45.4.0
   User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20160928132736
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) pophm.sympatico.ca:995, SSL, passwordCleartext
     OUTGOING: , smtphm.sympatico.ca:587, alwaysSTARTTLS, passwordCleartext, true

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

 Crash Reports

 Extensions
   Lightning, 4.7.4, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     accessibility.lastLoadDate: 1477767749
     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.filesystem_reported: 1
     browser.cache.disk.smart_size_cached_value: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     dom.apps.reset-permissions: true
     extensions.lastAppVersion: 45.4.0
     font.internaluseonly.changed: true
     font.name.monospace.el: 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.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.x-cyrillic: Cambria
     font.name.serif.x-unicode: Cambria
     font.name.serif.x-western: Cambria
     font.size.fixed.el: 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.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     general.autoScroll: false
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: dde95d00-c8f1-41dd-b719-573672193a0
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     network.cookie.cookieBehavior: 1
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1477348562
     places.history.enabled: false
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true

 Graphics

     Adapter Description: AMD Radeon(TM) R5 Graphics
     Vendor ID: 0x1002
     Device ID: 0x9851
     Adapter RAM: 1024
     Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
     Driver Version: 13.352.1004.1014
     Driver Date: 8-13-2014
     Direct2D Enabled: false
     DirectWrite Enabled: false (6.3.9600.18468)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon(TM) R5 Graphics Direct3D11 vs_5_0 ps_5_0) -- OpenGL ES 2.0 (ANGLE 2.1.0.316930d51ea9)
     GPU Accelerated Windows: 0

     AzureCanvasBackend: skia
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: cairo

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 1
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.12
     4.12

     NSS
     3.21.1 Basic ECC
     3.21.1 Basic ECC

     NSS Util
     3.21.1
     3.21.1

     NSS SSL
     3.21.1 Basic ECC
     3.21.1 Basic ECC

     NSS S/MIME
     3.21.1 Basic ECC
     3.21.1 Basic ECC

What happened in Safe Mode?

I beta tested 45 and am now using 50. It is tested before release and your situation is somewhat unusual. Safe Mode might indicate if an add-on is causing your issue.

Thanks for reply. As noted it won't open unless rebooted and I can't get the safe mode to start in any case. In case it helps I did uninstall and reinstall with no effect. There are no addons in TB but I do have them in FF. I will disable all of them and see if that helps

Don't bother with Firefox. It doesn't interact with Thunderbird.

How are you attempting to run Thunderbird in Safe Mode? Did you hold down shift when starting it? Also, check if your Start Menu entry for Thunderbird has a Safe Mode option.

Or create a new shortcut by copying the existing shortcut and edit the new shortcut's command line to add

-safe-mode

Make sure there is a space character before that leading hyphen.

You do have Lightning, and Safe Mode also disables customizations, plugins and video hardware acceleration.

Ok re-booted and got it to open in safe mode. Screen looks normal and buttons (like reply) seem to work.

And as an experiment. Closed it and re-started in normal with same old effect. A separate home screen where only way to inbox is right click and open to a new tab but most buttons don't work then.

And now it won't start at all (will need to reboot again).

Safe mode disables extensions. Lightning (the calendar add-on) is your only extension.

You can try to uninstall Ligfhtning via Add-ons Manager. Then re-install Lightning from AMO. https://addons.mozilla.org/thunderbird/addon/lightning/

If you don't use Lightning at all, you can simply disable it via Add-ons Manager. Does that fix the problem?

Thanks that is the problem. Removed the calendar and it works again.