See if the indexing needs a fix. Right click on folder and select 'Properties' click on 'Repair Folder' button click on OK

I tried this but it made it worse. What it did was match the header up with the detail. But the problem was the other way round. I now have two good copies of the first email and none of the second (the one where the contents no longer matched the header). The trouble with this is that I now no longer have an example of the bad email to try any other solution against. I shall have to wait for another example to appear.

It fixed the issue, it scanned you mail store and regenerated your index (the list) based on what it found. But as to the cause of the original problem, they could be many. But I would suggest you start by turning off email scanning in your anti virus and see if that stops further occurrences.

The only other possibility I see is an add-on, but as the issue is intermittent in appearance it would mean running for perhaps days without say a calendar to determine if such things were the cause.

Hi - it didn't fix the issue. the issue is that I'm losing message bodies. I've tried diasabling my add-ons off and that has not solved the issue. My antivirus is McAfee which works with an add-on so it's not that. I'm surprised nobody else has got this problem.

eramm01 said

Hi - it didn't fix the issue. the issue is that I'm losing message bodies. I've tried diasabling my add-ons off and that has not solved the issue. My antivirus is McAfee which works with an add-on so it's not that. I'm surprised nobody else has got this problem.

And I am surprised anyone using McAfee is still using Thunderbird after the total disaster McAfee has been since 2012 with non Microsoft mail clients.

Disable it from scanning your Thunderbird profile folder and remove any add-ons it installs. They tend to make Thunderbird quite unstable.

Agree with Matt I've got McAfee as it came with new computer by default, but made sure it did not put any addons in Thunderbird. That is just a no go area and asking for trouble.

The latest McAfee is a real pain and I'll soon get rid of it. There is no facility to exclude a Folder, you can only exclude files which is crazy when you think of how many files you are talking about when you do not want it messing around with any file in your profiles area. McAfee support forum is littered by many complaints about this.

I had disabled my McAfee add-on. I've now removed it. That has not solved the problem. I'm trying with my spam filter disabled now

Is this a POP or IMAP mail account ?

It's POP

As you say the emails are still on server in Inbox, it is possible to get another download. Suggest you move all emails out of your Inbox into suitably named folders. Then compact the Inbox folder.

Exit Thunderbird. Access your Profile folders. They are usually in this location for Windows OS.

• C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\ Mail\pop mail account name folder

In the pop mail account name folder, you will see a 'popstate.dat' file. The 'popstate.dat' file keeps a record of what has been downloaded to prevent Thunderbird from downloading emails that were previously downloaded. Delete the 'popstate.dat' file. When you restart Thunderbird, a new 'popstate.dat' file will be created. Thunderbird will then download all emails in the server Inbox to the pop mail account Inbox. Yes this means you will have duplicates, but hopfully this will correct the issue. You can then delete all the duplicates.

At the moment it seems to be solved. Once I looked at my spam folders I realised it was happening several times a day. I switched off my custom spam filters and I haven't had any problems since. I also compacted my inbox as you suggested. I didn't do the popstate delete because my ISP keeps all my old emails and there are nearly 49,000 of them. I didn't want to download all of them! The problem seems to have begun around the time I updated to 60.90.1 (early November) and seems to have been cured either by switching off my custom spam filters or by compacting the inbox. I'm not going to mark it as solved for another couplo' days just in case.

I have this problemn exactly and have tried all the suggestions above - but it still happens randomly every day. Message headers are correct but content is often a duplicate of a different email. All emails are correct on GMAIL. This also seemed to have started around early November when latest version of Thunderbird was installed. Compacting the inbox and repairing the inbox fixes it temnporarily