diff --git a/bin/vmail.sh b/bin/vmail.sh
index a6e9e10..9950c04 100755
--- a/bin/vmail.sh
+++ b/bin/vmail.sh
@@ -6,19 +6,29 @@
 #
 # vmail include file, used by other vmail bash scripts
 
-# any script that includes this conf file will force user to be vmail
-if [ "$USER" != "vmail" ]; then
-  exec sudo -u vmail --shell /bin/bash $0 $@
-fi
-
 # constants
 readonly VMAIL_DIR=/var/vmail
 readonly MYSQL_CONNECTION_INFO_FILE=$VMAIL_DIR/.my.cnf
 
-# check that MYSQL_CONNECTION_INFO_FILE exists and is readable
-if [ ! -f "$MYSQL_CONNECTION_INFO_FILE" ]; then
-  echo "ERROR: MySQL connection info file ($MYSQL_CONNECTION_INFO_FILE) does not exist or is not readable."
-  exit
+# switch to required user
+if [[ $(basename $0) == "vmail-dkim-"* ]]; then
+  if [[ "$USER" != "Debian-exim" ]]; then
+    exec sudo -u Debian-exim -g ssl-cert --shell /bin/bash $0 $@
+  fi
+elif [[ $(basename $0) == "vmail-purge-spool.sh" ]]; then
+  if [[ "$USER" != "Debian-exim" ]]; then
+    exec sudo -u Debian-exim --shell /bin/bash $0 $@
+  fi
+else
+  if [[ "$USER" != "vmail" ]]; then
+    exec sudo -u vmail --shell /bin/bash $0 $@
+  else
+    # check that MYSQL_CONNECTION_INFO_FILE exists and is readable
+    if [ ! -f "$MYSQL_CONNECTION_INFO_FILE" ]; then
+      echo "ERROR: MySQL connection info file ($MYSQL_CONNECTION_INFO_FILE) does not exist or is not readable."
+      exit
+    fi
+  fi
 fi
 
 # functions