Try safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.

Hello,

So I tried safe booting with Networking - but no joy - the same thing happened.

Here's the IMAP Log Output:

1188[7ef7920]: ImapThreadMainLoop entering [this=b6e7800] 0[250f140]: b6e7800:imap.googlemail.com:NA:SetupWithUrl: clearing IMAP_CONNECTION_IS_OPEN 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:ProcessCurrentURL: entering 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:ProcessCurrentURL:imap://user%40google-hosted%2Ecom@imap.googlemail.com:993/select%3E%5EINBOX: = currentUrl 1188[7ef7920]: ReadNextLine [stream=b607b68 nb=0 needmore=1] 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:CreateNewLineFromSocket: clearing IMAP_CONNECTION_IS_OPEN - rv = 804b000e 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:TellThreadToDie: close socket connection 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:CreateNewLineFromSocket: (null) 1188[7ef7920]: b6e7800:imap.googlemail.com:NA:ProcessCurrentURL: aborting queued urls 1188[7ef7920]: ImapThreadMainLoop leaving [this=b6e7800] 2188[7ef94b0]: ImapThreadMainLoop entering [this=254f800] 0[250f140]: 254f800:imap.googlemail.com:NA:SetupWithUrl: clearing IMAP_CONNECTION_IS_OPEN 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:ProcessCurrentURL: entering 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:ProcessCurrentURL:imap://user%40google-hosted%2Ecom@imap.googlemail.com:993/select%3E%5EINBOX: = currentUrl 2188[7ef94b0]: ReadNextLine [stream=8a874c8 nb=0 needmore=1] 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:CreateNewLineFromSocket: clearing IMAP_CONNECTION_IS_OPEN - rv = 804b000e 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:TellThreadToDie: close socket connection 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:CreateNewLineFromSocket: (null) 2188[7ef94b0]: 254f800:imap.googlemail.com:NA:ProcessCurrentURL: aborting queued urls 2188[7ef94b0]: ImapThreadMainLoop leaving [this=254f800] 1280[7ef94b0]: ImapThreadMainLoop entering [this=7e0d800] 0[250f140]: 7e0d800:imap.googlemail.com:NA:SetupWithUrl: clearing IMAP_CONNECTION_IS_OPEN 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:ProcessCurrentURL: entering 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:ProcessCurrentURL:imap://user%40google-hosted%2Ecom@imap.googlemail.com:993/select%3E%5EINBOX: = currentUrl 1280[7ef94b0]: ReadNextLine [stream=884b1a8 nb=0 needmore=1] 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:CreateNewLineFromSocket: clearing IMAP_CONNECTION_IS_OPEN - rv = 804b000e 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:TellThreadToDie: close socket connection 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:CreateNewLineFromSocket: (null) 1280[7ef94b0]: 7e0d800:imap.googlemail.com:NA:ProcessCurrentURL: aborting queued urls 1280[7ef94b0]: ImapThreadMainLoop leaving [this=7e0d800]

I also ran the error console and found:

Timestamp: 21/03/2015 07:46:30 Warning: mutating the Prototype of an object will cause your code to run very slowly; instead create the object with the correct initial Prototype value using Object.create Source File: resource://gre/components/steelApplication.js Line: 783

Could not read chrome manifest 'file:///C:/Program%20Files%20(x86)/Mozilla%20Thunderbird/chrome.manifest'.

Could not read chrome manifest 'file:///C:/Program%20Files%20(x86)/Mozilla%20Thunderbird/extensions/%7B972ce4c6-7e08-4474-a285-3208198ce6fd%7D/chrome.manifest'.

--- for what it's worth I'm happy to do a clean reinstall (which I did, removed the user's profile, removed the application and reinstalled, it complained about the proile, so ran with profile manager, and it installed).

Any help appreciated :)

I should also menntion -- I previously had other imap connections to other systems (not google ones) and they also failed.

Trouble Shooting Information:

 Application Basics

   Name: Thunderbird
   Version: 31.5.0
   User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150222233048
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (imap) imap.googlemail.com:993, SSL, passwordCleartext
     OUTGOING: smtp.googlemail.com:465, SSL, passwordCleartext, true

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

 Crash Reports

 Extensions

 Important Modified Preferences

   Name: Value

     browser.cache.disk.capacity: 358400
     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
     extensions.lastAppVersion: 31.5.0
     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
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: b4b19134-6aed-4453-a513-b6cf492aecc
     network.cookie.prefsMigrated: true
     plugin.importedState: true

 Graphics

     Adapter Description: Intel(R) HD Graphics 3000
     Vendor ID: 0x8086
     Device ID: 0x0116
     Adapter RAM: Unknown
     Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32
     Driver Version: 9.17.10.2828
     Driver Date: 7-31-2012
     Direct2D Enabled: true
     DirectWrite Enabled: true (6.2.9200.16384)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: false
     GPU Accelerated Windows: 1/1 Direct3D 10

     AzureCanvasBackend: direct2d
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: direct2d

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.10.6
     4.10.6

     NSS
     3.16.2.3 Basic ECC
     3.16.2.3 Basic ECC

     NSS Util
     3.16.2.3
     3.16.2.3

     NSS SSL
     3.16.2.3 Basic ECC
     3.16.2.3 Basic ECC

     NSS S/MIME
     3.16.2.3 Basic ECC
     3.16.2.3 Basic ECC

So after all that - it's the router!

Turns out the router has a really lame and lazy "Firewall". When in "high security" mode it only allows for HTTP/HTTPS. When in "medium security" mode it allows IMAP, SSH, etc.