All that and all I get is the possibility that you did some diagnostics and it worked in safe mode. Be that Thunderbird's or Windows I can only guess.

So how about we try dealing with this as a support request as you are in the support forum.

Please add the troubleshooting information to your post To find the Troubleshooting information:

• Open Help (or click on three-line-icon and select Help)
• Choose Troubleshooting Information
• Use the button Copy to clipboard to select all. Do not check box "Include account names"!
• Paste this in your post.

Please also add the result of these troubleshooting steps to your post

• Does Thunderbird work in TB Safe mode (see Thunderbird Safe Mode)?
• Do you use anti-virus and firewall software? What is the version?
• Who is the email provider?
• Who is the internet provider?
• What is the exact error message, if you get one?

Application Basics

   Name: Thunderbird
   Version: 45.5.1
   User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20161130024037
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account3:
     INCOMING: account3, , (imap) 192.168.2.2:143, alwaysSTARTTLS, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account4:
     INCOMING: account4, , (imap) 192.168.2.2:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account5:
     INCOMING: account5, , (imap) 192.168.2.2:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account6:
     INCOMING: account6, , (imap) tascgrp.mine.nu:143, alwaysSTARTTLS, passwordCleartext
     OUTGOING: , mail.bigpond.com:25, plain, none, true

   account8:
     INCOMING: account8, , (imap) 192.168.2.60:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account15:
     INCOMING: account15, , (imap) imap.tascgrp.com:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account16:
     INCOMING: account16, , (imap) imap.tascgrp.com:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account17:
     INCOMING: account17, , (imap) imap.tascgrp.com:143, plain, passwordCleartext
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

   account18:
     INCOMING: account18, , (imap) imap.tascgrp.com:143, plain, passwordEncrypted
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordCleartext, true

   account20:
     INCOMING: account20, , (imap) imap.tascgrp.com:143, plain, passwordEncrypted
     OUTGOING: , smtp.tascgrp.com:587, plain, passwordEncrypted, true

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-2399812f-912c-44e1-aecb-8baac2161206 (06/12/2016)
   http://crash-stats.mozilla.com/report/index/bp-d333a5d6-38f5-4c06-a1a9-01db42161204 (04/12/2016)
   http://crash-stats.mozilla.com/report/index/bp-c17d0c37-b3c6-437f-bf1e-0611e2161114 (14/11/2016)
   http://crash-stats.mozilla.com/report/index/bp-74add99a-e5bf-4172-a0b5-f1f802161019 (19/10/2016)
   http://crash-stats.mozilla.com/report/index/bp-2fc017df-3ad0-4507-bd35-3ae012160927 (27/09/2016)

 Extensions
   Lightning, 4.7.5.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     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
     dom.gamepad.extensions.enabled: true
     extensions.lastAppVersion: 45.5.1
     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.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
     gfx.crash-guard.glcontext.appVersion: 45.4.0
     gfx.crash-guard.glcontext.deviceID: 0x100c
     gfx.crash-guard.glcontext.driverVersion: 21.21.13.6909
     gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true
     gfx.crash-guard.status.glcontext: 2
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 5a51149b-b099-43a4-ade9-39341b0ca3a
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"5"},"flaggedCol":{"visible":true,"ordinal":"7"},"attachmentCol":{"visible":false…
     mailnews.database.global.views.global.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     media.gmp.storage.version.observed: 1
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1481521843
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true

Matt,

Thunderbird does not start straight away in Safemode. I will Shift, click on the icon and it wont fire up until I click on the Icon again then asks if I was to continue in safemode.

I get no error messages.

You can email me for security information such as firewall type etc...

Thanks for your help.

Thunderbird still doesnt work properly, yet I am able to access my mail on my webmail server just fine.

It just hangs, and takes a long time to process anything.

I am not over my quota so that is not an issue but I am getting similar complaints from other people that I have recommended Thunderbird to.

One person hit the send button, went away for 3 hours then came back and it was still sending.

I am receiving what seems to be echoing of emails as when they finally do come through, they come through 5 to 10 times.

The won;t be caused by Thunderbird in this case. Look for other causes. Start point is Start windows in safe mode.