Junk will get emptied if you have set up Thunderbird to empty it.

You will need the following settings:

• Account Settings
• Select 'Junk Settings' for the account

DEstination and Retention:

• Select 'Move new junk messages to:

If POP:

• Select 'Junk folder on' and choose email address of account.

If IMAP:

• Select 'Other' and choose 'Spam on mail account/email address'

DO NOT select the checkbox 'Automatically delete junk mail older than...

Please note: If this is an Imap mail account then you may discover the server is automatically deleting the contents of the Spam folder.

Also check the Global Settings:

• Settings > Privacy & Security
• Scroll to 'Junk' section
• Select: When I mark messages as junk
• Select 'Move them to the accounts junk folder
• Select 'Enable adaptive junk filter logging

Also check Junk/Spam folder:

• Right click on folder and select 'Properties'
• On 'Retention Policy' tab
• Select 'Use my account settings'
• Select 'Don't delete any messages'

Thanks, I did most of those yesterday. I am now seeing current items in the junk folder and the sent folder shows what I have sent since yesterday. One big question I have is why this just suddenly happened yesterday. I did not change the settings at all, and it deleted all my sent and all my junk. Do you know of any way to get them back short of going to my backup. I shouldn't have to do this.

Are you using a POP or an IMAP mail account ? What server are you talking about? eg: gmail, BT, Yahoo, gmx, etc

Check to see if folder index file is out of synch with mail storage file try this to fix:

• Right click on 'Sent' folder an select 'Properties'
• click on 'Repair Folder'
• click on 'OK'

What Anti-Virus product are you using ? Do you use anything like CCleaner or WiseCleaner to clean up files? Do you allow Anti-Virus or any cleanup program to scan Thunderbird profile folders ? If AV finds an issue they can try to fix the problem, but these products do not understand that one file may contain many emails and it's all too easy to lose all emails in a file. Ideally, you do not want any of those products scanning your profile folders. If you really want to use those products then make Thunderbird profile folder exempt from scanning. If you really do want AV to scan profile folders then make sure it must ask what to do and under no circumstances say fix it. But it should offer info on what it does not like so you can locate the problem manually, delete the offending email and then compact the folder.

It is IMAP. I tried the sent file repair, but no help. I don't use the Cleaners. I have a gmail address, but I use Thunderbird for email. My phone provider provides the anti virus, and they checked the account yesterday. They were afraid I got hacked, but doesn't look like it. Once I changed the defaults back (that is the mystery...How did my preferences get changed to delete junk, and purge sent after 3 days) it appears to be working the way I want. Thanks for your help. Could have been worse.

Posted as a new question.