Indeed, Kmail is the worst emailing client I have ever used ! Not only it's terribly slow, it doesn't prompt any meaningful message to show you what's happening in the background when you move folders, but I also just lost about 10000 mails in one folder (while the other 7000 are still in this same folder) without apparent reason or any warning message. Any hope to get these back (they were removed from the mail server)?

It is understandable that you are frustrated with shortcomings from KMail: however, your post does not give any information on how people might actually help you.

A few questions:

- Which version of KDEPIM are you using?
- Were you using any filters?
- What kind of account types did you use?