re :Today I boot up Thunderbird to see that hundreds of emails are missing from my thunderbird account.

There is no such thing as a Thunderbird account, so I presume you mean a mail account for a specific email address.

re :There are two other emails in my thunderbird that are unaffected by this event.

I'm not so sure you mean two emails are still showing - do I presume you mean you have 2 other mail accounts for 2 different email addresses and they work ok?

Meaning you have 3 mail accounts in Thunderbird.

Regarding the problem email address mail account: Check to see if you have any filters operating which are hiding emails.

• Menu icon > View > Folders > select 'All'
• Menu icon > View > Threads > select 'All'

You mention hundreds of email are missing - Q: Do you mean the folder is empty? Or do you mean it is only displaying new mail ? Q: Is it possible you have a filter selected so it only shows eg: unread.

• Select 'Inbox'

Q: Are any of the icons on the 'Quick Filter Bar' selected and that includes the 'pin' icon?

• If yes, please click on them to deselect.

Please provide some information so we can offer more tailored information. Q: Is this an Imap or POP mail account ? Q:Can you see all the folders? Q:Are all folders empty or just one eg: Inbox ?

Explain what you mean by 'hundreds of emails missing' - do you have empty folders or are you only seeing emails with a recent date ?

Q:If Imap - logon to webmail account using a browser. Are all the folders and emails are still on server?

Hello,

    Yes, you are right in that I mean a mail account. I have three mail accounts. 

I have already looked to other threads that have suggested removing any filters.

No, I do not have only unread selected or only displaying new mail. None of the options of the quick filter bar are selected either.

I am using an imap account. I went to the webmail account using a browser and all of the emails are missing there as well. 

The only thing that is odd is I logged onto my home pc to check the email and for about 3 seconds all of my old emails were there, and promptly disappeared. All the more frustrating, knowing that it may have been deleted due to a server error? This has only affected the inbox, not the sent folder or other folders.

The reason I mention the other mail accounts is because they are all fine just as they were. Let me know if you have other advice.

re : I went to the webmail account using a browser and all of the emails are missing there as well......The only thing that is odd is I logged onto my home pc to check the email and for about 3 seconds all of my old emails were there, and promptly disappeared.

It meant emails were in imap account until it synchronised with server. As emails were not on server and imap account synchronises with server to display what is on server, those emails would be removed from the imap account. So, there is nothing odd about that particular aspect.

I'm not sure whether you have more than one computer or whether you only have the one home computer. For example: If you had seen emails disappear from one computer accessing via imap and then logged on to webmail to discover emails missing off server, you would have needed to have backed up the profile folders on the other 'home' computer before starting Thunderbird. Then they could have been imported back into 'Local Folders' account and then gradually copied back into the imap account to put back on server.

So, the question is: Do you have a backup of your Thunderbird profile? Do you have another computer which accesses same account using imap and you have not started it up? If yes, do not start Thunderbird on that computer as it may contain a copy of emails, but that depends upon whether you download full copies or headers. You may need to backup the profile before you use it.

Do not close Thunderbird as I'm not sure if you have it set up to compact on exit.

• Do not compact any folders.
• You may need to access Account Settings > Server Settings and uncheck 'Clean up (Expunge) Inbox on Exit.
• So check the Settings now before proceeding.

Please try this to see if you can recover emails.

In Thunderbird

• 'Help' > ' More Troubleshooting Information'
• click on 'open folder'

a new window opens showing profile folder name

• Close Thunderbird now - this is important
• Right click on 'Mail' folder to open in a new window - you will need this later.
• click on 'ImapMail' folder
• click on imap mail account name that has missing emails.

you should see the 'Inbox' mbox file - it has no extension.

• Copy that 'Inbox' (no extension) file

• Go to the window you previosly opened showing contents of 'Mail' folder
• Click on 'Local Folders' folder to see contents.
• Paste that copied 'Inbox' file into 'Local Folders'
• Rename it as 'OldInbox'
• Open the 'OldInbox' file using Notepad

Emails are written to the file one after the other, so oldest will be at the top and newest at the bottom. Each email will start with these lines: this is an example

• From - Sun Dec 28 18:14:40 2014
• X-Mozilla-Status: 0001
• X-Mozilla-Status2: 00800000

Use 'Edit' > 'Find' This may end up marking all as unread but hopefully you may recover deleted mail.

• Look for this line: X-Mozilla-Status: (not X-Mozilla-Status2:)
• Make sure the X-Mozilla-Status: has the number 0001
• Work down through the file setting the X-Mozilla-Status line to 0001
• Save the file.
• Restart Thunderbird.

Start Thunderbird Look in 'Local Folders' mail account for the 'OldInbox' Compare number of emails with the imap Inbox. Does it have a greater number - if yes, then it looks like you have recovered some emails.