Possible reason - filter is operating, so only a selection is visible. Select 'Sent' folder For Sent folder make sure there are no filters operating. eg: Quick Filter bar - is anything selected - if yes uncheck everything and clear the search. Make sure this is selected

• View > Threads > All

Possible reason emails not on server. Is this an imap mail account ? If yes, logon to webmail account and check the 'Sent' folder on server. Do you see all Sent emails back before 03.08.23. ? If no, then Thunderbird cannot display what does not exist.

If yes, when you logon to webmail account, is the name of the 'Sent' folder actually called 'Sent' or 'Sent Mail' or 'Sent Items' ?

Possible reason wrong folder synchronised or limit on download. In Imap account in Thunderbird

• Right click on imap name folder in Folder Pane and select 'Subscribe'
• Click on 'Refresh'
• You need to select whatever the sent folder is called on the server eg: 'Sent Mail'
• Click on 'Subscribe'
• click on 'OK'

Then check setting:

• Account Settings >Copies & Folders for imap account
• Select 'Place a copy in'
• Select 'Other' and choose 'Sent Mail on imap account'

Check you are downloading full copies:

• Select 'Synchronisation & Addressing'
• Click on 'Advanced' button
• make sure 'Sent Mail' is selected
• click on Ok
• Under 'Disk Space'
• select 'Synchronise all messages locally regardless of age'

Hello @Toad-Hall , Thank you very much for the help , but nothing was successful for me . On my webmail is the same , no emails in Sent folder before 03.08.23 :( Any other idea ?

re :On my webmail is the same , no emails in Sent folder before 03.08.23 :(

If you have an imap mail account then it can only display what is on the server as seen via webmail. As the emails do not exist on server then it is impossible for them to exit in an imap account no matter whether it is Thunderbird, Outlook or EMClient etc. That only explains why you cannot see them in Thunderbird imap account.

Suggest you check to see what is actually in the profile folders, just in case something occured like a new imap account was created so the original still has an old sent file or maybe it created a new sent file and the old original still exists.

First check where the imap account is pointing - what is the profile name and what is the actual name of the account it is using.

• Account Setting > Server Settings for the account
• Look bottom right for 'Local directory:...'
• Make window wide enough to see all the text in the 'Local directory' text box.
• Please copy it and paste it into this forum OR create an image which shows info and post image.

This means I can sure where that account is storing mail.

You mention an update, but I'm not sure what version you are running. Currently, Thunderbird is not updating to the new supernova 115* - that can only occur if you download and install it. If you were directed to update to that version then it was not Thunderbird. It means you have updater software program on your computer and it suggested that update not understanding Thunderbird is still updating 102* eg: 102.13.1 updates to 102.14.0

In Thunderbird

• If you are running 115.1.0 - Help > Troubleshooting Information
• If you are running 102.14.0 - Help > More Troubleshooting Information

• Under 'Application Basics' - half way - Profile Folders - click on 'Open Folder'

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

• Exit Thunderbird now.
• Click on 'ImapMail' folder (it contains all imap accounts)

What do you see ?

• Please post an image showing contents of that 'ImapMail' folder - so I can understand what if anything has occurred.

One of the imap mail account folders will have identical name to the one mentioned in 'Local directory:...' If there are more than one - maybe one has same name but with an additional number do the following.

• click on each imap account name folder you see to check contents.
• Make sure you have the files displaying details, so you see columns 'Name', 'Modified date', 'Type' and 'Size' and they are sort by 'Name'.
• Post an image showing contents of each imap mail account folder so I can understand what is stored, where it is stored, what size and when it was modified.

In the imap account name folder you should see: mbox text files if you are downloading full copies of emails. They are files with same name as folders you see in Folder Pane. These files do not have any extension and they contain emails. Also files with the extension .msf - these are index files used by Thunderbird and they do not contain emails. You may see folders with .sbd extension. they are created when you have subfolders and they may contain mbox files etc.

You are looking for 'Sent' which is likely to be the current file and possibly files of same name with additional number eg: 'Sent-1'.

You can open these 'sent' files using 'Notepad' if size less than 512MB or 'Notepad++' if size less than 2GB. Oldest email will be at the top. Do any of those 'Sent' files have an email at the top which is older than 03.08.23 ?

If No no sent emails older than 03.08.23 : then you will need to see if server has a load of deleted sent emails - check Trash folder OR whether those emails got archived and are now in an 'Archive' folder. If server is a gmail style which uses labels then it may have something like an 'All Mail' folder - so check webmail to see if has that type of folder. It may have sent emails that have no sent label. They just need to have sent label reapplied. Last alternative - do you have a backup of Thunderbird created at an earler date?

IF yes you see sent emails older than 03.08.23 : then do this.

• Copy the 'Sent/Sent-1' file
• Go up directory to 'profile name' folder
• Select 'Mail' folder to see contents
• Select 'Local Folders' folder to see contents
• Paste the copied 'Sent/Sent-1' file into Local Folders folder.

Start Thunderbird Check the 'Local Folders' folder

Upon updating to 115 all my Sent emails, all 1,700 of them were deleted. Fortunately I had a backup and was able to click and drag them from the previous 102 to the 115 Sent folder. But why did the update delete all the emails? Interestingly, my laptop is windows 10, but my wife who did the same update on her windows 11 desk top lost nothing! Is this windows 10/11 dependent thing? BTW we use the portable version of Thunderbird.

Upon updating to 115 all my Sent emails, all 1,700 of them were deleted. Fortunately I had a backup and was able to click and drag them from the previous 102 to the 115 Sent folder. But why did the update delete all the emails? Interestingly, my laptop is windows 10, but my wife who did the same update on her windows 11 desk top lost nothing! Is this windows 10/11 dependent thing? BTW we use the portable version of Thunderbird.

It might be something to do with the portableapp version of Thunderbird.

If you had an imap account, then maybe you just needed to check you had subscribed to the correct Sent server folder and make sure it was subscribed to be seen in order to see everything that is held on the server.

If you had a pop mail account, then maybe the emails were in the pop 'Sent' mbox file (not sure if you found that mbox file empty or not) but the index file was out of sync in which case you could have tried:

• a right click on 'Sent' pop folder
• select 'Properties'
• click on 'Repair Folder'
• Click on 'OK'