Repair Plesk Mailboxes

~# /usr/local/psa/admin/sbin/mchk --help
 Restore settings for all mailboxes.
 Usage: /usr/local/psa/admin/sbin/mchk [OPTION]

 OPTIONS:
   --without-spam   restore all settings except for SpamAssassin configuration
   --with-spam      restore all settings
   --spam-only      restore only SpamAssassin settings

 Usage example:

~# /usr/local/psa/admin/sbin/mchk --with-spam