Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.

Matt, I'm afraid that didn't help. It shows everything disabled (plugins, extensions, etc.) and still won't receive new email automatically or if I hit Get Messages. It does not show any add-ons installed.

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

• Do you use anti-virus and firewall software? What is the version?
• Who is the email provider?
• Who is the internet provider?

-I use McAfee Internet security, version 14, release 14.0 R10. -The email provider that I'm having trouble with is Charter. I actually have both Charter and my Gmail account on Thunderbird. Gmail seems to update automatically and when I click Get Messages, but not the Charter account. However, it used to. -Internet provider is also Charter. Below is the troubleshooting info. (Thanks for any help!)

 Application Basics

   Name: Thunderbird
   Version: 45.4.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; 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, , (imap) imap.charter.net:143, plain, passwordCleartext
     OUTGOING: , smtp.charter.net:25, plain, passwordCleartext, true

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

   account3:
     INCOMING: account3, , (imap) imap.gmail.com:993, SSL, OAuth2
     OUTGOING: , smtp.gmail.com:465, SSL, OAuth2, true

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-e9ab11dd-fdc6-4088-84fd-90ed12140121 (1/21/2014)

 Extensions
   Lightning, 4.7.4, false, {e2fda1a4-762b-4020-b5ad-a41df1933103}
   McAfee Anti-Spam Thunderbird Extension, 2.0, false, msktbird@mcafee.com

 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
     extensions.lastAppVersion: 45.4.0
     font.internaluseonly.changed: false
     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
     gfx.crash-guard.glcontext.appVersion: 45.4.0
     gfx.crash-guard.glcontext.deviceID: 0x68f9
     gfx.crash-guard.glcontext.driverVersion: 8.960.11.1000
     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
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 50dbcaf5-72db-4a6e-bb36-55a65c3782e
     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: 1478211479
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     print.printer_Brother_MFC-J450DW_Printer.print_bgcolor: false
     print.printer_Brother_MFC-J450DW_Printer.print_bgimages: false
     print.printer_Brother_MFC-J450DW_Printer.print_duplex: -437918235
     print.printer_Brother_MFC-J450DW_Printer.print_edge_bottom: 0
     print.printer_Brother_MFC-J450DW_Printer.print_edge_left: 0
     print.printer_Brother_MFC-J450DW_Printer.print_edge_right: 0
     print.printer_Brother_MFC-J450DW_Printer.print_edge_top: 0
     print.printer_Brother_MFC-J450DW_Printer.print_evenpages: true
     print.printer_Brother_MFC-J450DW_Printer.print_footercenter:
     print.printer_Brother_MFC-J450DW_Printer.print_footerleft:
     print.printer_Brother_MFC-J450DW_Printer.print_footerright:
     print.printer_Brother_MFC-J450DW_Printer.print_headercenter:
     print.printer_Brother_MFC-J450DW_Printer.print_headerleft:
     print.printer_Brother_MFC-J450DW_Printer.print_headerright:
     print.printer_Brother_MFC-J450DW_Printer.print_in_color: true
     print.printer_Brother_MFC-J450DW_Printer.print_margin_bottom: 0.300000011920929
     print.printer_Brother_MFC-J450DW_Printer.print_margin_left: 0.5
     print.printer_Brother_MFC-J450DW_Printer.print_margin_right: 0.5
     print.printer_Brother_MFC-J450DW_Printer.print_margin_top: 0.300000011920929
     print.printer_Brother_MFC-J450DW_Printer.print_oddpages: true
     print.printer_Brother_MFC-J450DW_Printer.print_orientation: 0
     print.printer_Brother_MFC-J450DW_Printer.print_page_delay: 50
     print.printer_Brother_MFC-J450DW_Printer.print_paper_data: 1
     print.printer_Brother_MFC-J450DW_Printer.print_paper_height: 11.00
     print.printer_Brother_MFC-J450DW_Printer.print_paper_name:
     print.printer_Brother_MFC-J450DW_Printer.print_paper_size_type: 0
     print.printer_Brother_MFC-J450DW_Printer.print_paper_size_unit: 0
     print.printer_Brother_MFC-J450DW_Printer.print_paper_width: 8.50
     print.printer_Brother_MFC-J450DW_Printer.print_resolution: -437918235
     print.printer_Brother_MFC-J450DW_Printer.print_reversed: false
     print.printer_Brother_MFC-J450DW_Printer.print_scaling: 0.80
     print.printer_Brother_MFC-J450DW_Printer.print_shrink_to_fit: true
     print.printer_Brother_MFC-J450DW_Printer.print_to_file: false
     print.printer_Brother_MFC-J450DW_Printer.print_unwriteable_margin_bottom: 0
     print.printer_Brother_MFC-J450DW_Printer.print_unwriteable_margin_left: 0
     print.printer_Brother_MFC-J450DW_Printer.print_unwriteable_margin_right: 0
     print.printer_Brother_MFC-J450DW_Printer.print_unwriteable_margin_top: 0

 Graphics

     Adapter Description: ATI Radeon HD 5450
     Vendor ID: 0x1002
     Device ID: 0x68f9
     Adapter RAM: 512
     Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
     Driver Version: 8.960.11.1000
     Driver Date: 4-25-2012
     Direct2D Enabled: false
     DirectWrite Enabled: false (6.2.9200.21976)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: Google Inc. -- ANGLE (ATI Radeon HD 5450 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: 0
   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

Wrt McAfee see https://wiki.mozilla.org/Thunderbird:Testing:Antivirus_Related_Performance_Issues#McAfee

Wrt Charter: There was a similar problem with GoDaddy a while ago which did affect many people, and GoDaddy were simply denying there was a problem at all. In the end they silently fixed it, whatever the problem was.

GoDaddy reference fyi: https://bugzilla.mozilla.org/show_bug.cgi?id=1260724#c10

Even though not recently anymore there have been a lot of complaints in this forum from people using Charter about the very same problem. You'll need to complain to Charter. Tell them you're not the only one with the problem.

IIRC the issue is charter IMAP does not wrap folder names in quotes after the initial download. So subsequent fetches fail because the folder names are not correctly quoted by the server software

Guess I just can't use thunderbird with my charter email then unless I open and close it all the time. I'm sure charter won't do anything about it. It did work previously so they must have changed in the past year. Bummer!