I recently upgraded from kubuntu-10.04 to kubuntu-12.04, and have had a great deal of difficulty with kmail2. I finally seemed to have gotten past all the various blockers, but now, suddenly, whenever I try to send email, the composer windows greys out for up to 10-15 minutes. During that time, if I click on an email folder I get the 'Retrieving Folder Contents' message, and I am unable to read the body of any previously downloaded email.

Eventually, the email is sent out and kmail2 starts operating 'normally' again. 'Normal' being a relative term, since under 'normal' conditions I still get periodic notifications like 'Local Folders are broken', 'failed to move email to sent-mail folder' and other such disturbing messages, although the app seems to be operating properly.

I tried to use the 'send mail later' feature so that I can queue the mail and send it at a later time, but the behavior is the same. I am also testing evolution, and it is not having any issues sending email, so it's not an issue with my ISP.

Restarting kmail2 clears the issue briefly, but it returns invariably.

Has anyone else experienced this sort of behavior?

It is a known bug: currently the issue is being discussed by the KDEPIM developers, who are reviewing solutions these days (because it's going to be fixed in likely two different ways for 4.9.x and 4.10).