VM transfers the mail from a spool file to a folder via a temporary
file known as the "crash box". The variable `vm-crash-box' names the
crash box file for the primary inbox. Or a crash-box name may be
created from `vm-crash-box-suffix' described below. (*note Spool
Files::.) VM first copies the mail to the crash box, truncates the
spool file to zero messages, merges the crash box contents into the
primary inbox, and then deletes the crash box. If the system or Emacs
should crash in the midst of this activity, any message not present in
the primary inbox will be either in the spool file or the crash box.
Some messages may be duplicated but no mail will be lost.


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