Simon Josefsson <jas@extundo.com> writes:

> Try (setq debug-on-quit t) and post the backtrace you get when
> pressing C-g.  I think *imap-log* content would be useful too, be sure
> to kill the buffer before pressing 'g' so you only get fresh data.

Hi,

I attached the backtrace and the imap-log.  Minibuffer said
  nnimap: Mailbox Trash modified
before I hit C-g.

Hope this will show what's going wrong ...