Dmitry Streblechenko wrote:
I have never seen or heard about such a problem with MailItem.Save.
I strongly suspect that something happens in your code :-)

I know, it sounds very suspicious. (For me, too ;-) But now, when I
Save an Item that has not been saved previously I call ActiveWindow()
and GetCurrentItem() again (basically re-getting the pointer) and it
works. I've removed the QueryInterface-Call to the GetCurrentItem()
result, so there shouldn't be memory leaks.

Don't ask me why, but it works.

Dmitry, thanks a lot for all your help and comments!