Try repairing the index file: Right click on 'Inbox' folder and select 'Properties' click on 'Repair folder' Click on OK

Select another folder and then reselect 'Inbox'.

That's made it worse. I've lost all the messages and the headers. The file size shown has now gone down from 5200 to 286 messages with everything before the crash now totally gone - headers and all. Everything else has now disappeared.

No it did not make it worse. The index file does not contain any emails, it just has pointers to emails. If it had pointers in the index and they pointed to nothing then you would be seeing the headers, but when selected, there would be no email content because it was not there. Repairing the index forces it to get up to date with what is actually stored. So, this means the emails had already gone or are hidden because they were deleted.

So when you said " so it looks as if something in an index might have got corrupted?" you were right in that the index was telling you something was there and it wasn't.

The mbox file that contained the emails was open at the time of the power cut and computer crash on Sunday and this caused the loss of data.

What we do not know is whether the emails exist but have been 'marked as deleted' and 'hidden'.

So you need to find out whether this is the case.

In Thunderbird

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

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

• Close Thunderbird now - this is important because you cannot edit files currently in use.

• If talking about a POP account - click on 'Mail' folder to see contents
• click on pop mail account name folder to see contents.

In Thunderbird, emails are stored in mbox text files. mbox text files do not have any extension. You should see a file called 'Inbox' (not 'Inbox.msf' - this is an index file)

• Open the 'Inbox' no extension mbox file using a text editing program like Notepad.

Emails are written to the file in the order they are downloaded or created, so the oldest will be at the top.

If you can see those emails that are not displaying in the Thunderbird Inbox folder for the account then do the following:

Each email will start with these lines: this is an example

• From - Sun Dec 28 18:14:40 2014
• X-Mozilla-Status: 0019
• X-Mozilla-Status2: 00800000

I've included a couple of example images to help show you what I'm talking about.

• Use 'Edit' > 'Find'

Starting at the top use 'Edit' > 'Find' to help to look for this line:

• X-Mozilla-Status: ( - NOT this line: X-Mozilla-Status2:)

• Make sure each X-Mozilla-Status: line has the number 0001

• Edit the number as required changing to say 0001 working down through the document. Take your time.
• Save the file.
• Delete the 'Inbox.msf' indexing file. A new one will be auto created.
• Start Thunderbird.

If you do not find the old deleted emails, do you have a backup of your thunderbird profile folder?

baccma,

Is this Inbox in an imap account? And did Toad-Hall's instructions help??

No sorry, it is a POP3 account but most of the emails are no longer on the server but Toad-Hall's instructions did help in a way, and I've now answered that. Thanks.

Toad-Hall: Thanks, I took me a while to get around to it this week. The underlying email file was a bit of a mess, but using an old back-up and then cutting and pasting messages from the MBox file got everything back bar a few attachments which I can live without (probably downloaded somewhere even if ever needed). It was understanding what had happened, and the additional confidence that it wasn't difficult to play around with the file contents that really helped, so thanks a lot for the detailed explanation. M