Do you use a product like CCleaner to clean up temp files ? If yes, then do not let CCleaner anywhere near any Thunderbird files or folders as this type of product has a habit of deleting passwords, session data before it has updated files etc and it can cause all kinds of havoc. If you really want to use any product like CCLeaner, then make sure all Thunderbird files and folders are exempt. Do this before starting Thunderbird.

What type of account are you talking about? Is it Pop or IMAP ?

If Pop:

• Help > Troubleshooting Information
• click on 'Open Folder' button

a new window opens showing the contents of your 'profile name' folder.

• Exit Thunderbird now - this is important.
• Click on 'Mail' folder
• click on pop mail account name folder.

You should see two files for each folder name. One will just have the folder name and no extention. This is an mbox file and it contains emails. Do not delete this file. Right click on each mbox file in turn and select 'Properties' under 'Attributes' 'read only' and 'hidden' should not be selected, so uncheck them if they have been selected and click on OK.

Index files will have same name but they will have a .msf extension. Index files are used by Thunderbird. They do not have any emails in them. Delete files that end in .msf with exception of 'Inbox.msf' as it is displaying ok. Restart Thunderbird.

If Imap: See if you need to subscribe again to see server folders.

• Right click on imap mail account name in Folder Pane and select 'Subscribe'
• click on 'Refresh' button
• Select/highlight all folders and subfolders that you want to see.
• Click on 'Subscribe' button
• click on 'OK'

What OS are you using? Is account Pop or Imap? Are you using a product like CCleaner ? What Anti-Virus product are you using?

Did you find that mbox files had 'Properties' with 'Attributes' set as 'read only' and/or 'hidden' ?

Please report back with information and results.

I also have this problem. The sub folders in my email have disappeared. I right clicked folder pane. Subscribe. All the subfolders were there complete with ticks. Clicked subscribe and refresh. Didn't work. Removed and replaced ticks subscribe/refresh - no difference.

Richard Check you have this setting: Menu icon (3 lines) > 'View' > 'Folders' > select 'All'

If this does not show sub folders: Assuming you are using Windows OS and everything is in default location. Check to see if all is correct in the profile folders.

Access: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\ ImapMail\'mail account name' folder.

A quick way of getting to profile folder: In Thunderbird Help > Troubleshooting Information click on 'Open Folder' then click on 'ImapMail' folder to open Click on the mail account name folder to open

Please post images showing contents of the mail account name folder.

You will have *.sbd folders. click on *.sbd folder to open Please post images showing contents of the *.sbd folder(s).

Soory to be thick. This is what I found when opening folder in Troubleshoooting information

Troubleshooting Information This page contains technical information that might be useful when you’re trying to solve a problem. If you are looking for answers to common questions about Thunderbird, check out our support website. Include account names (possibly identifying information) Application Basics Name Thunderbird Version 60.9.0 Build ID 20190902145622 Update History Update Channel release User Agent Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0

Tried going via C;.. using run/%appdat%, and clicked ....spd folder, and was told it was empty OS Windows_NT 10.0 Profile Folder (Local drive) Enabled Plugins about:plugins Build Configuration about:buildconfig Memory Use about:memory Performance about:performance Registered Service Workers about:serviceworkers Multiprocess Windows 0/0 (Disabled) Stylo content = true (enabled by default), chrome = true (enabled by default) Google Location Service Key Missing Google SafeBrowsing Key Missing Mozilla Location Service Key Missing Safe Mode false Profiles about:profiles Mail and News Accounts ID Incoming server Outgoing servers Name Connection security Authentication method Name Connection security Authentication method Default? account1 (imap) imap4.blueyonder.co.uk:993 SSL/TLS Normal password smtp.blueyonder.co.uk:465 SSL/TLS Normal password true account2 (none) Local Folders None Normal password account3 (im) prpl-gtalk None 0 Crash Reports for the Last 3 Days Report ID Submitted

All Crash Reports Extensions Name Version Enabled ID Lightning 6.2.9 true {e2fda1a4-762b-4020-b5ad-a41df1933103} Theme Font & Size Changer for Thunderbird 64.6 true [email protected]

I have tried again with the missing folder problem. Got to .sbd folders and found a list of these files including "deletede", "Trash" etc. Also the following files Inbox.spd - which contained all the missing subfolders, 55 in total and inbox-2.spd inbox-21.spd inbox-22.spd

of thse, 2 and 22 wwere identical,containing just 5 of the complete list of folders 21 contained 4 of the folders in 2 and 22

Does this make sense.

re :In Thunderbird Help > Troubleshooting Information (Note : 'Help' is also in the Menu icon drop down menu) click on 'Open Folder' See image below.

re :I have tried again with the missing folder problem. The info sounds like you are in the correct area.

re:Does this make sense. It makes sense even if rather odd, but for thunderbird to know what folders it is suppose to open I need to check all the file names.

So I need to see images of the content to ensure all the correct files are in the account.

After clicking on 'Open Folder' button, a new window opens showing content of your 'profile name' folder. click on 'ImapMail' folder to open the folder Click on the imap mail account name folder to open it. I need to see what you are currently looking at. Please post image showing all the contents in the imap mail account name folder.