Does this also occur if your disable email scanning in your anti virus program?

Hi ... turned off email scanning (Norton 360) and the problem remains. Message only occurs on startup of the program, not subsequent checks for email, whether scheduled or manual. Op system is Win 8.1 pro 64 with all current patches.

before sending you off to file a bug....

Press shift+F5. Does this bring up the extra password request.?

Shift + F5 has no action while I'm in the program reading your message.

shift F5 should force a mail download for all accounts.

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.

Here's the troubleshooting info: BTW I have only one mail account in Thunderbird ... a Gmail account.

 Application Basics

   Name: Thunderbird
   Version: 38.0
   User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150522020825
   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
   http://crash-stats.mozilla.com/report/index/bp-02a415f6-c620-4257-a850-3886f2150526 (5/26/2015)
   http://crash-stats.mozilla.com/report/index/bp-1b8ac822-b35a-4908-b96b-9c5412150512 (5/12/2015)
   http://crash-stats.mozilla.com/report/index/bp-32e980d6-78af-4eb8-8187-d8dce2150511 (5/10/2015)
   http://crash-stats.mozilla.com/report/index/bp-bf11078d-75bb-46b7-8666-614312150322 (3/22/2015)
   http://crash-stats.mozilla.com/report/index/bp-6333d279-1279-4642-b85b-7815d2150322 (3/22/2015)

 Extensions
   Google Contacts, 0.7.12, true, {BDD92442-0534-4D6F-A966-BAB7D561D781}

 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
     browser.display.background_color: #CCFFFF
     dom.max_chrome_script_run_time: 0
     extensions.lastAppVersion: 38.0
     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: Tahoma
     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
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.enable: true
     mail.winsearch.firstRunDone: true
     mail.winsearch.global_reindex_time: 1383090212
     mailnews.database.global.datastore.id: 423d69e5-4314-4aec-ac33-310bfcf631a
     mailnews.database.global.indexer.enabled: false
     network.cookie.cookieBehavior: 3
     network.cookie.lifetimePolicy: 2
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1432680254
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     print.printer_HP_Officejet_7310.print_bgcolor: false
     print.printer_HP_Officejet_7310.print_bgimages: false
     print.printer_HP_Officejet_7310.print_colorspace:
     print.printer_HP_Officejet_7310.print_command:
     print.printer_HP_Officejet_7310.print_downloadfonts: false
     print.printer_HP_Officejet_7310.print_duplex: 0
     print.printer_HP_Officejet_7310.print_edge_bottom: 0
     print.printer_HP_Officejet_7310.print_edge_left: 0
     print.printer_HP_Officejet_7310.print_edge_right: 0
     print.printer_HP_Officejet_7310.print_edge_top: 0
     print.printer_HP_Officejet_7310.print_evenpages: true
     print.printer_HP_Officejet_7310.print_footercenter:
     print.printer_HP_Officejet_7310.print_footerleft: &PT
     print.printer_HP_Officejet_7310.print_footerright: &D
     print.printer_HP_Officejet_7310.print_headercenter:
     print.printer_HP_Officejet_7310.print_headerleft: &T
     print.printer_HP_Officejet_7310.print_headerright: &U
     print.printer_HP_Officejet_7310.print_in_color: true
     print.printer_HP_Officejet_7310.print_margin_bottom: 0.5
     print.printer_HP_Officejet_7310.print_margin_left: 0.100000001490116
     print.printer_HP_Officejet_7310.print_margin_right: 0.100000001490116
     print.printer_HP_Officejet_7310.print_margin_top: 0.5
     print.printer_HP_Officejet_7310.print_oddpages: true
     print.printer_HP_Officejet_7310.print_orientation: 0
     print.printer_HP_Officejet_7310.print_page_delay: 50
     print.printer_HP_Officejet_7310.print_paper_data: 1
     print.printer_HP_Officejet_7310.print_paper_height: 11.00
     print.printer_HP_Officejet_7310.print_paper_name:
     print.printer_HP_Officejet_7310.print_paper_size_type: 0
     print.printer_HP_Officejet_7310.print_paper_size_unit: 0
     print.printer_HP_Officejet_7310.print_paper_width: 8.50
     print.printer_HP_Officejet_7310.print_plex_name:
     print.printer_HP_Officejet_7310.print_resolution: 0
     print.printer_HP_Officejet_7310.print_resolution_name:
     print.printer_HP_Officejet_7310.print_reversed: false
     print.printer_HP_Officejet_7310.print_scaling: 0.95
     print.printer_HP_Officejet_7310.print_shrink_to_fit: false
     print.printer_HP_Officejet_7310.print_to_file: false
     print.printer_HP_Officejet_7310.print_unwriteable_margin_bottom: 0
     print.printer_HP_Officejet_7310.print_unwriteable_margin_left: 0
     print.printer_HP_Officejet_7310.print_unwriteable_margin_right: 0
     print.printer_HP_Officejet_7310.print_unwriteable_margin_top: 0
     privacy.donottrackheader.enabled: true

 Graphics

     Adapter Description: NVIDIA GeForce GT 240
     Vendor ID: 0x10de
     Device ID: 0x0ca3
     Adapter RAM: 512
     Adapter Drivers: nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um
     Driver Version: 9.18.13.4052
     Driver Date: 7-2-2014
     Direct2D Enabled: true
     DirectWrite Enabled: true (6.3.9600.17795)
     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: 1
   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

Looking through that there was a crash yesterday )or was that today your time) anyway.

The crash indicated you have lavasoft ad aware or other lavasoft product installed. (it inserts itself in to the operating system TCP/IP stack). What happens if it is uninstalled? The only other recent crash with the same signature was windows XP and they to had non MS entries in their TCP/IP stack is why I am asking here.

Barely functional TCP could also account for some very strange interface events. Slowness being only one.

Does the problem get worse if you select the get mail button?

I will try uninstalling that later today. It's been in place for many versions, though without a problem, and doesn't exhibit any other symptoms, such as slowness. Today is a very busy day for me and it will take me a few hours to get to this and to follow up with you.

AdAware is installed in Firefox but not specifically in Thunderbird. I disabled it there and restarted the PC. Without opening Firefox, I started Thunderbird and it exhibits the same problem.

Incidentally, the request for password does not keep TB from retrieving the mail from this (the only) account. It logs in and gets the mail while the PW request screen is still up.

The password prompt is for Google Contacts. See https://support.mozilla.org/en-US/questions/1064153

The developer may have abandoned the Google Contacts add-on. So there most likely will not be an update anytime soon. I'd therefore disable the add-on in Add-On manager for the time being to avoid the password prompts in the first place.