Restart Thunderbird. Try to delete a message.
What happens?

I already tried, but nothing happens. The massage just stays where it is.

Try to rebuild the index file of the troubled folder.
Right-click the folder - Properties - Repair Folder

Sorry, but the entire folder has gone.

Can you be a little more descriptive?

Several years I'm using Thunderbird now. My desktop uses Windows 7. A few days ago when I started Thunderbird after a while I noticed I could not delete any message. All other functions still work as before. Searching for why I could not delete messages I found out that I missed the folder 'recycle bin' (in Dutch: 'prullenbak'). So my question is how to restore this folder. All other folders are intact and working, just except this one. As it is a systemfolder I cannot make a new one myself.

I meant to repair the folder you cannot delete messages from.

I'm very sorry, but I cannor repair any folder. When I click on 'repair' it seems to happen, but after that nothing has changed.

Nothing changed is success usually.

Is the account in question IMAP or POP?

it's a POP account

Sounds like the 'Deleted' folder is full and so no more emails can be deleted. But if folder is greyed out or you cannot select it, try to force an empty folder.

Try this:

• 'Tools' > 'Account Settings' > 'Server settings' for the account
• at the bottom under 'Message Storage'
• select 'empty Deleted folder on Exit'
• click on OK

Close Thunderbird and allow some time for deleting to occur. Then restart Thunderbird and see if the 'Deleted' folder is now available.

you can always change the option to' empty deleted fodler on exit' after restarting.

Thanks. I have selected 'empty Deleted folder on Exit' but nothing changes.

Try this to repair the Trash index.

make hidden folders visible:

• http://kb.mozillazine.org/Show_hidden_files_and_folders

location of Profile folders

• http://kb.mozillazine.org/Profile_folder_-_Thunderbird

In Thunderbird:

• Help > Troubleshooting Information
• click on 'show Folder'
• A new window will open showing Profile Folder

• Close Thunderbird Now - this is important.
• Click on 'Mail' folder
• click on the pop mail account name
• look for Trash.msf and delete the file
• Close window - top right X
• Open Thunderbird

the index file should be rebuilt, did this get the Trash to appear?

• If yes, right click on Trash and choose 'Empty TRash'
• then right click on Trash and select 'compact'

Thank you. It didnot solve the problem at once. But after that I opened a backup file from before the date the trash folder disappeared, and included the trash and trash.msf in the current folder. After starting up Thunderbird again I got the trash folder again and I can use it again. Thanks a lot!