you clicked on what to fix what. I am sorry but that is insufficient information to even guess what you did.

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

• Does Thunderbird work in TB Safe mode (see Thunderbird Safe Mode)?
• Do you use anti-virus and firewall software? What is the version?
• Who is the email provider?
• Who is the internet provider?
• What is the exact error message?
• What steps did you take right before this happened?

Please post back with this information and any other questions you might have.

Hi Matt, thanks for responding.

I don't know what I clicked on, I was just flailing about trying to fix one of 3 problems for which I have found no help using the help function:

1: I can't export e-mails to .eml files in a desktop folder as I could with some earlier versions of Thunderbird. 2: A system Integration window pops up every time I start Thunderbird. 3: The one I was most likely working on--I'm on a new computer and I set my three accounts to POP. My main Gmail account sent a few hundred old e-mails, most of them showing as unread. I wanted to find a way to do a bulk "mark as read" on them, planning to sort through them later.

In Safe mode with both boxes checked all my accounts and their sub-folders show up. I set Thunderbird to fetch mail on startup so what I see on normal startup is the inbox of each account that has new messages.

I use Sophos for AV and firewall.

The e-mail providers are gmail (2 accounts) and look.ca, my old dialup ISP.

There is no error message.

As I said above, I don't know what I was doing. I think I was in account settings but am not certain.

I don't know how attach a file to a post so troubleshooting information follows:

 Application Basics

   Name: Thunderbird
   Version: 45.5.1
   User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20161130024037
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) pop.gmail.com:995, SSL, passwordCleartext
     OUTGOING: , smtp.gmail.com:465, SSL, OAuth2, true

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

   account3:
     INCOMING: account3, , (pop3) mail.look.ca:110, alwaysSTARTTLS, passwordEncrypted
     OUTGOING: , smtp.gmail.com:465, SSL, OAuth2, true

   account4:
     INCOMING: account4, , (pop3) pop.gmail.com:995, SSL, passwordCleartext
     OUTGOING: , smtp.gmail.com:465, SSL, OAuth2, true

 Crash Reports

 Extensions
   Lightning, 4.7.5.1, false, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     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: 45.5.1
     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.blacklist.direct2d: 3
     gfx.blacklist.suggested-driver-version: 15.2010.1151.0
     gfx.crash-guard.glcontext.appVersion: 45.5.1
     gfx.crash-guard.glcontext.deviceID: 0x9874
     gfx.crash-guard.glcontext.driverVersion: 15.201.1101.1002
     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
     mailnews.database.global.datastore.id: fd440ee9-69a5-4d30-a40b-0ac82726a8b
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1481386772
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     privacy.donottrackheader.enabled: true

 Graphics

     Adapter Description: AMD Radeon(TM) R6 Graphics
     Vendor ID: 0x1002
     Device ID: 0x9874
     Adapter RAM: 512
     Adapter Drivers: aticfx64 aticfx64 aticfx64 amdxc64 aticfx32 aticfx32 aticfx32 amdxc32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
     Driver Version: 15.201.1101.1002
     Driver Date: 8-21-2015
     Direct2D Enabled: Blocked for your graphics driver version. Try updating your graphics driver to version 15.2010.1151.0 or newer.
     DirectWrite Enabled: false (10.0.10586.0)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon(TM) R6 Graphics 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
     3.21.3 Basic ECC
     3.21.3 Basic ECC

     NSS Util
     3.21.3
     3.21.3

     NSS SSL
     3.21.3 Basic ECC
     3.21.3 Basic ECC

     NSS S/MIME
     3.21.3 Basic ECC
     3.21.3 Basic ECC

I still can't tell what you have done to hide your folders. Most likely, it seems to me, is that somewhere you selected an option to show, for example, only unread messages, or only folders containing unread messages. Running in Safe Mode may have undone this option.

To work with multiple messages, such as to mark them read, you select them. There are standard keystrokes and mouse click techniques to do this.

http://xenos-email-notes.simplesite.com/417754237

As an aside, I have an observation about your account settings. Account 3, which is your look.ca account, is set to use gmail for sending. Maybe you have attached the look.ca email address to your gmail account. But if you haven't, any messages sent using your look.ca address as the "From:" address will appear to the recipient as having come from your gmail address.

Having noticed this, I'd also check that your second gmail account also has its own distinct SMTP set-up, otherwise it too will have the wrong From: address.

Thanks Zenos, you helped solve one of my problems I know how to group select but I didn't know how to mark as read. But in looking at it I realized that the top menu shows in safe mode and I found a "mark as read" setting there. I also found an import option in tools but unfortunately could not find an export option.

You also gave me a hint at solving the main problem. If there is an option somewhere to show only folders containing unread items and I inadvertently clicked it that would explain the vanished folders. I have looked for a menu that has such an option but have not found it.

Re: the aside. My sent e-mails show the right "from" address in the "sent" folders of the gmail accounts. I'm not sending anything from Look.

Thanks,

Derek

You have now twice mentioned things that no one has asked for. You don't need to attach a file (you did the right thing by pasting the Troubleshooting Information). And now you're talking about an export option. Why?

BTW the system integration prompt is a bug in the current version. Apparently there will be a fix "real soon now".

Dang! My first reply to your last post has gone missing.

Hidden folders: View|Folders|Unread might hide some folders. Change it to "All".

Marking messages: try right-click. It's faster than searching through menus.

From address: with Gmail, you need to check what the recipient sees. Gmail silently swaps out the From: address. Try sending a message to your look.ca address and check who it gives as the sender in the message in your Inbox.

Zenos, thank you for your help.

As you suggested I tried sending to Look from my gmail accounts. Both showed the correct "from" address.