Your description gives me the impression that Thunderbird is being prevented from updating files. They often 'appear' as changed, but when thunderbird closes, the files aren't updated. When that happens, the file is saved with extension, such as inbox-1, inbox-2. You might also check to see if the prefs.js is suffering as well, possibly showing multiple copies. You might try pausing your antivirus to see if that affects the issue. I am not an expert at all on issues such as this, but what you describe are the symptoms.

As I wrote in my original message I have put the Thunderbird profile in the excluded section of my antivirus software. I also tried turning off the antivirus live scanning for a short time to see what difference it made. None.

Ok, a possibility is that the prefs.js file is set to read-only. Again, I'm no guru in this category, but something is blocking the saving of files. My hope is that someone with more knowledge on this issue sees the thread.

In answer to David's previous question there are 2 prefs.js files: prefs.js and prefs-1.js - but the prefs1.js is dated 19/9/2024, which is before the problems I have been having for the last few days.

As an update, I am gradually solving some of the problems. But one thing I am finding is that folders that I have deleted come back again. I deleted all the contents of a folder earlier today (90 messages which for some reason are taking up 9.2 GB) and emptied the Deleted box. But now exactly the same emails are back in that folder!

Also what are these folders that keep appearing under the Deleted box - not sub-folders of the Deleted Box. They have names like Inbox.msf-1.compact-backup which has 1 message in it which looks like it may be a coded index and is reported as 6.1MB. Can I just delete them or do they contain imporatant information - they have only been appearing in the last few days.

My inference is that the deletion appears while TB is still running. When it closes, it fails in updating the folder. So, on a restart, the messages are still there. The two prefs files is further proof of the problem. any msf file can be deleted, as TB reconstructs on restart. Resolving the problem is beyond my ability. Generally, with thunderbird not running, you can rename the prefs.js to prefs.old and rename the highest-numbered prefs to prefs.js and restart. That may help, as it will usually be more current than the other.

Thank you David for persevering with this, especially as no-one else seems to be stepping in.

I went to the prefs.js files. The prefs-1.js file is older than the prefs.js file, so I did not change it.

I seemed to be gradually getting on top of the problem but yesterday I suddenly found that there were now 2000 emails in my Inbox and I was missing all of the emails from 1 Jan- 1 Jun 2024 from my Inbox. There should ahve been about 11,000 emails. I keep all of this year's emails in my Inbox and archive everything from previous years. When I clicked Properties on my Inbox, it showed 11,000 so I thought that by clicking "Repair Folder" it would reindex and restore the missing emails. Instead it deleted them all.

I back-up overnight every night so I went to my backup - but whatever had happened must have happened before my overnight backup because the Inbox on the Backup only has 2000 emmails as well and is the same size as the present Inbox so obviously the 11,000 emails are not there. They are not in Archives or deleted either - so I guess I have permanently lost these. My worry is that since no-one has explained what is going on, I fear that I may wake up tomorrow with even more emails deleted.

I suggest you take drastic action.

1. do a full backup of profile with thunderbird not running
2. revert to ver 115 from https://ftp.mozilla.org/pub/thunderbird/releases/115.16.2/win64/en-US/
3. you can install over the top of current version, and BE SURE to set to NOT UPDATE AUTOMATICALLY

I do not mean to imply that 128 is the culprit, but this has all happened since the upgrade.

When exactly did the upgrade from 115 to 128 occur? I would be interested to know as it might correlate with my problems. I had my Thunderbird set to automatic updates so I didn't find out when the update occured.

When exactly did the upgrade from 115 to 128 occur? I would be interested to know as it might correlate with my problems. I had my Thunderbird set to automatic updates so I didn't find out when the update occured.

Help > Troubleshooting Information > Show Update History

I started to do as suggested by David above to install 115 over the 128 version but then I came to the message:

"A newer version of Thunderbird may have made changes to your profile which are no longer compatible with this older version. Use this profile only with that newer version, or create a new profile for this installation of Thunderbird. Creating a new profile requires setting up your accounts, calendars and add-ons again."

If I complete this Thunderbird 115 installation, can I use profile manager to point Thunderbird to my existing profile and retrieve all my accounts, directory set up, passwords etc. exactly as I have it on my present 128 setup or does the above message mean I have to set everything up again?

Look in the profile for a file named compatibility.ini and delete it then start thunderbird

Is that while I still have TB 128 before I install TB 115 or after I install 115?

after installing 115

Thanks - I now have 115 installed and it seems to be showing me my configuration. I went into Settings. There seems to be no setting that says "No updating" so I chose "Check for updates, but let me choose whether to install them". I also unchecked "Use a background service to install updates" - although I don't know what that means.

I hope that has solved the problem but only time will tell. Before I installed 115 I was looking through some of my Local Archives files and I see that some directories have single or multiple copies of some email messages. I think that means these duplicate messages must have overwritten existing emails because the overall number of messages is about right. I wonder what other havoc I will find.

I suppose this means that I will be stuck in 115 forever as I cannot think of how I will findout that Thunderbird has fixed the problem I was having as I cannot pinpoint the cause and no-one stepped into this thread to give a definite diagnosis. So I will not be able to tell whether this problem has been fixed from the descriptions of the bugs fixed at each update. And I don't want to risk the loss of more emails by justing trying a new update out to see if the problem is fixed or not.

Should I leave this thread open or mark it as "Solved the problem"?

I consider it solved, as you now have the setting to not upgrade automatically. Thank you,

Did we determine that none of the files was read-only?

I am not sure how to determine that and I guess it is too late now as I have already installed 115