https://support.mozilla.org/en-US/kb/cannot-receive-messages

Well I don't have a route to the server settings as illustrated for a start. I don not have tools - preferences. I can get to the server settings but why would they suddenly change, I have not messed with them? Richard

I don't have a route to the server settings

Press Alt-T

why would they suddenly change, I have not messed with them?

The point really is to check whether your Thunderbird server settings still match the server settings required by your email provider. In other words, check whether the settings required by your provider have changed.

Yes they do, but I cannot find how to check whether the email password is correct, where on earth is that stored? Richard

Ok. I deleted the half written reply.

Have you got the menu bar turned on? Right click the toolbar and select menu bar. None of the instructions you get will make much sense if it is turned off. If you don't understand my instructions try these. https://support.mozilla.org/en-US/kb/display-thunderbird-menus-and-toolbar

Next follow instructions. Your doing a lot of replying, but getting information is like pulling teeth. If your password is wrong you will be told and a dialog will open asking for a new password. At this point your going off on a tangent with the password. Tools menu > options > security > passwords and press the show passwords button to see your saved passwords.

Do I take your interest in where they are stored as some sort of clue as to some error message your getting that you have not yet mentioned?

BT and their email system is a total mess. As I understand it they are in the process of moving from one failed mail provider contract to another with is just as poor. From what I have read here, you would be unlikely to act on advice emailed to you by BT about email. So 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 post back with this information so we have something to check.

Given Thunderbird has just updated my first guess however would be your anti virus is not coping with the change and needs attention. But as a BT customer with their mess we must start at the beginning and verify your account settings.

when i get to passwords, there are none. I do not have a show passwords option and if I select saved passwords there are none... Could this be the problem..... (incidentaly I recently lost all my old e mails from before May 5th, from what you say this might have something to do with BT, I assumed it would be pointless to try and get any sense out of BT) See below: Richard

 Application Basics

   Name: Thunderbird
   Version: 38.0.1
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150608103712
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

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

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

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-c42056b7-cac8-4365-8c45-f11b82150624 (24/06/2015)
   http://crash-stats.mozilla.com/report/index/bp-230fde46-bb17-46eb-8e79-696332150624 (24/06/2015)

 Extensions
   Lightning, 4.0.0.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     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: 38.0.1
     font.internaluseonly.changed: true
     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: Comic Sans MS
     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: e9ccc729-bc09-4078-934e-76030b197d1
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1435161932
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     print.printer_hp_deskjet_940c.print_bgcolor: false
     print.printer_hp_deskjet_940c.print_bgimages: false
     print.printer_hp_deskjet_940c.print_colorspace:
     print.printer_hp_deskjet_940c.print_command:
     print.printer_hp_deskjet_940c.print_downloadfonts: false
     print.printer_hp_deskjet_940c.print_duplex: 1515870810
     print.printer_hp_deskjet_940c.print_edge_bottom: 0
     print.printer_hp_deskjet_940c.print_edge_left: 0
     print.printer_hp_deskjet_940c.print_edge_right: 0
     print.printer_hp_deskjet_940c.print_edge_top: 0
     print.printer_hp_deskjet_940c.print_evenpages: true
     print.printer_hp_deskjet_940c.print_footercenter:
     print.printer_hp_deskjet_940c.print_footerleft: &PT
     print.printer_hp_deskjet_940c.print_footerright: &D
     print.printer_hp_deskjet_940c.print_headercenter:
     print.printer_hp_deskjet_940c.print_headerleft: &T
     print.printer_hp_deskjet_940c.print_headerright: &U
     print.printer_hp_deskjet_940c.print_in_color: true
     print.printer_hp_deskjet_940c.print_margin_bottom: 0.5
     print.printer_hp_deskjet_940c.print_margin_left: 0.5
     print.printer_hp_deskjet_940c.print_margin_right: 0.5
     print.printer_hp_deskjet_940c.print_margin_top: 0.5
     print.printer_hp_deskjet_940c.print_oddpages: true
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     print.printer_hp_deskjet_940c.print_paper_data: 9
     print.printer_hp_deskjet_940c.print_paper_height: 11.00
     print.printer_hp_deskjet_940c.print_paper_name:
     print.printer_hp_deskjet_940c.print_paper_size_type: 0
     print.printer_hp_deskjet_940c.print_paper_size_unit: 1
     print.printer_hp_deskjet_940c.print_paper_width: 8.50
     print.printer_hp_deskjet_940c.print_plex_name:
     print.printer_hp_deskjet_940c.print_resolution: 1515870810
     print.printer_hp_deskjet_940c.print_resolution_name:
     print.printer_hp_deskjet_940c.print_reversed: false
     print.printer_hp_deskjet_940c.print_scaling: 1.00
     print.printer_hp_deskjet_940c.print_shrink_to_fit: true
     print.printer_hp_deskjet_940c.print_to_file: false
     print.printer_hp_deskjet_940c.print_unwriteable_margin_bottom: 0
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     print.printer_hp_deskjet_940c.print_unwriteable_margin_right: 0
     print.printer_hp_deskjet_940c.print_unwriteable_margin_top: 0

 Graphics

     Adapter Description: Intel(R) HD Graphics 4000
     Vendor ID: 0x8086
     Device ID: 0x0166
     Adapter RAM: Unknown
     Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32
     Driver Version: 8.15.10.2618
     Driver Date: 1-5-2012
     Direct2D Enabled: true
     DirectWrite Enabled: true (6.2.9200.17292)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: false
     GPU Accelerated Windows: 1/1 Direct3D 11

     AzureCanvasBackend: direct2d 1.1
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: direct2d 1.1

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.10.8
     4.10.8

     NSS
     3.18.1 Basic ECC
     3.18.1 Basic ECC

     NSS Util
     3.18.1
     3.18.1

     NSS SSL
     3.18.1 Basic ECC
     3.18.1 Basic ECC

     NSS S/MIME
     3.18.1 Basic ECC
     3.18.1 Basic ECC

PS. I have Kaspersky security

When it get to passwords, there are none. I do not have a show password option and if I select saved passwords there are none... Could this be the problem?

Would that be Kaspersky Total Security if so disable the password manager http://support.kaspersky.com/7971

I don't seem to have a password manager button on my Kaspersky page as shown, just four boxes scan, update, safe money, and parental controls...? Richard

PS. I only have Internet Security, guess it is different?