I presume you mean you can see the list of emails, but upon selection they appear blank in the Message pane? Are you talking about a pop or imap mail account?

It is possible the index is not correct. It is also possible the emails do not exist. right click on 'Sent' folder and select 'Properties' click on 'Repair folder' button click on OK

If the emails appear then the index file was at fault. If the list of emails now disappears as well then either the emails do not exist, hence why you could not read them or they have been marked as deleted and therefore hidden.

Do not compact any folders.

It is possible that your Anti-Virus product has scanned and 'fixed' the 'sent' folder. Not a good idea as AV products do understand that an mbox file is not one email, but a file of emails. Maybe the AV product only quarrantined the file and not fixed it. AV product would have left the indexing file alone, hence why it was out of synch with mbox file.

Check to see if emails really do exist, but just not showing: In thunderbird

• Help > TRoublshooting Information
• click on 'show folder'

a new window opens showing profile folder name

• Close Thunderbird now - this is important

you should see 'Mail' and 'ImapMail' folders If pop

• click on 'Mail' folder
• click on pop mail account name

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

• Open the 'Sent' file using Notepad or Notepad++ or other Text Editor

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' Starting at the top use the look for this line: X-Mozilla-Status: It will have a number eg: 0009 Make sure each X-Mozilla-Status: has the number 0001

edit the number as required working down through the document. Save the file. delete the 'Sent.msf' file. A new one will be auto created. Restart Thunderbird.

that should get emails back in Thunderbird Sent Report back on whether this worked.

there seems to be an error in between 2009 and jan 2017 , when i try to scroll up, notepad freezes and does not recover.

Maybe this has something to do with the size of file.

Try Notepad++.