Recovering Emacs sessions

Emacs hung for some reason, and I had to forcibly kill it. When I tried to do `recover-session' in a new Emacs session, all kinds of problems appeared.

1. The IMAP cache folders were recovered, but there was no easy way to know what IMAP folders they corresponded to. Moreover, these buffers were in Fundamental mode or Text mode. I don't know what problems arise if `vm-mode' is turned on in them. I didn't bother. I just killed all those modified buffers, losing the changes in the process.

2. The message composition buffers were recovered, but again they were in Text mode. Trying to turn on `vm-mail-mode' in them doesn't work. Apparently, there is no such mode.

The manual says how to recover mail folders and advises using `vm-recover-folder'. Since `recover-session' does `recover-file', one should not recover VM folders in this way. This is a bummer! The manual should at least mention that.

The manual says nothing about what to do with message composition buffers.