Are these folders on IMAP mail accounts?

Not sure how I would find this out. When I check under Account Settings, it reads "Outgoing server (SMTP): "Google Mail - smtp.googlemail.com (Default)" Not sure if this is the information you need or not. Thanks for any help.

In order for us to better investigate this issue you need to add a little more non-personal information.

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.

Thanks.

 Application Basics

   Name: Thunderbird
   Version: 45.4.0
   User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.4.0
   Profile Folder: Show in Finder
   Application Build ID: 20160928113259
   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

   account3:
     INCOMING: account3, , (pop3) pop.storm.ca:110, plain, passwordCleartext
     OUTGOING: , mail.storm.ca:587, alwaysSTARTTLS, passwordCleartext, true

   account5:
     INCOMING: account5, , (imap) imap.googlemail.com:993, SSL, passwordCleartext
     OUTGOING: , smtp.googlemail.com:465, SSL, passwordCleartext, true

 Crash Reports
   http://crash-stats.mozilla.com/report/index/bp-19254fa3-f3a4-4abc-843d-6ea362160406 (2016-04-06)
   http://crash-stats.mozilla.com/report/index/bp-24d3cacd-3b59-4786-907e-80d442160318 (2016-03-18)
   http://crash-stats.mozilla.com/report/index/bp-54c73990-460c-423b-a7f1-ac3382150213 (2015-02-13)
   http://crash-stats.mozilla.com/report/index/bp-6442e885-42b4-49db-a857-bbdb12130402 (2013-04-02)
   http://crash-stats.mozilla.com/report/index/bp-b0bbf3f6-f094-4142-9d2d-b5c932130304 (2013-03-03)

 Extensions
   Lightning, 4.7.4, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}
   Test Pilot for Thunderbird, 1.3.10, true, tbtestpilot@labs.mozilla.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
     browser.zoom.full: true
     extensions.lastAppVersion: 45.4.0
     font.internaluseonly.changed: true
     font.name.sans-serif.x-western: Arial
     font.size.variable.x-western: 12
     gfx.blacklist.direct2d: 3
     gfx.blacklist.layers.direct3d9: 3
     gfx.crash-guard.glcontext.appVersion: 45.4.0
     gfx.crash-guard.glcontext.deviceID: 0x9488
     gfx.crash-guard.status.glcontext: 2
     mail.openMessageBehavior.version: 1
     mail.spotlight.enable: true
     mail.spotlight.firstRunDone: true
     mail.spotlight.global_reindex_time: 1284686522
     mailnews.database.global.datastore.id: 432792c3-a303-b545-8e43-6bd5e8e9fbc
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     mailnews.database.global.views.global.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: 1479313655
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     print.macosx.pagesetup-2: PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz4KPCFET0NUWVBFIHBsaXN0IFBVQkxJQyAiLS8vQXBwbGUvL0RURCBQTElTVCAxLjAvL0VO…
     print.print_bgcolor: false
     print.print_bgimages: false
     print.print_command:
     print.print_downloadfonts: false
     print.print_evenpages: true
     print.print_in_color: true
     print.print_margin_bottom: 0.5
     print.print_margin_left: 0.5
     print.print_margin_right: 0.5
     print.print_margin_top: 0.5
     print.print_oddpages: true
     print.print_orientation: 0
     print.print_pagedelay: 500
     print.print_paper_data: 0
     print.print_paper_height: 11.00
     print.print_paper_size_type: 1
     print.print_paper_size_unit: 0
     print.print_paper_width: 8.50
     print.print_printer:
     print.print_reversed: false
     print.print_scaling: 1.00
     print.print_shrink_to_fit: true
     print.print_to_file: false
     print.print_unwriteable_margin_bottom: 17
     print.print_unwriteable_margin_left: 17
     print.print_unwriteable_margin_right: 17
     print.print_unwriteable_margin_top: 17
     privacy.donottrackheader.enabled: true
     security.disable_button.openCertManager: false

 Graphics

     Vendor ID: 0x1002
     Device ID: 0x9488
     WebGL Renderer: ATI Technologies Inc. -- ATI Radeon HD 4670 OpenGL Engine -- 2.1 ATI-10.2.8
     GPU Accelerated Windows: 0

     AzureCanvasBackend: skia
     AzureSkiaAccelerated: 1
     AzureFallbackCanvasBackend: none
     AzureContentBackend: quartz

 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

If it is one of our Google accounts then it is IMAP. For the folder to be greyed, the google server is advising it is not available for update.