File menu (alt+F) > compact folders.

Right click the account, select settings and in server settings select expunge on exit.

Corrected question. When I white a new mail, then Thunderbird display: Kan ikke kopier til meddelsen til mappen KLADDE (can´t copy to DRAFT) and when I send the mail, I get the message: Kan ikke kopier meddelelse til mappen SENDT (Can`t send the message to folder SEND) Compress folder did not work in this case and server settings is selected. I have compressed all folders and rep. index file. The result is still the same. In the local folder there is no problem.

re: server settings have 'expunge on exit' selected. I presume you are using IMAP. Please answer the following to help us understand your set up.

1. Please confirm that you have restarted Thunderbird to force the expunge to work.

2. Please, right click on mail account name and click on 'subscribe' to check you are still subscribed to see the sent and Draft folders. Confirm you have subscribed to see the imap server Sent and Drafts folders. (they may have a slightly different name eg: 'Sent Items')

3. Check your Account Settings....do you have these settings?

Tools > Account Settings > 'Copies & Folders' for imap mail account. When sending messages, automatically: select: 'Place a copy in' Select: 'Other' and 'Sent folder on the imap mail account.

Under 'Drafts and Templates' Keep message drafts in: Select: 'Other' and drafts folder on the imap mail account.

Click on OK

If this a gmail imap mail account then settings should be: Sending: Do not save sent messages on the server. If your client is sending mail through Gmail's SMTP server, your sent messages will be automatically copied to the [Gmail]/Sent Mail folder. In Thunderbird this would mean: When sending messages, automatically: Uncheck: 'Place a copy in' it will grey out the sent options.

Ok we have addressed what can be done locally. Your account is IMAP and your mail provider gives you a disk space allowance for storing your mail. You are currently at 103& of that allocation so saving more mail to folders is not occuring. Quite likely the receipt of new mail is also bouncing until you bring your stored mail under the quota of space your provider allows.

Move messages to Local folders to remove them from the server and retain local copies on your PC.