Comment 2 for bug 723081

I do indeed mean it is doing unnecessary save operations when I manually run vm-save-folder. The indication in the mode line is "--" (no asterisks).

To reproduce, open a gmail account, start with an empty ~/.vm, add the following settings, then start emacs and vm, and run vm-expunge-imap-messages.

("imap-ssl:imap.gmail.com:993:inbox:login:<email address hidden>:*")
(setq vm-imap-expunge-after-retrieving nil)

Even when there is no indication that the buffer is modified, it will re-save your inbox buffer when you run vm-save-folder after running vm-expunge-imap-messages on the unmodified buffer, even if no messages were expunged.