diff --git a/target/scripts/start-mailserver.sh b/target/scripts/start-mailserver.sh
index 56dfa1fb..af800730 100755
--- a/target/scripts/start-mailserver.sh
+++ b/target/scripts/start-mailserver.sh
@@ -36,6 +36,7 @@ function _register_functions() {
   _register_check_function '_check_improper_restart'
   _register_check_function '_check_hostname'
   _register_check_function '_check_log_level'
+  _register_check_function '_check_spam_prefix'
 
   # ? >> Setup
 
diff --git a/target/scripts/startup/check-stack.sh b/target/scripts/startup/check-stack.sh
index cf1c40f5..a650474d 100644
--- a/target/scripts/startup/check-stack.sh
+++ b/target/scripts/startup/check-stack.sh
@@ -52,3 +52,12 @@ function _check_log_level() {
     LOG_LEVEL="${DEFAULT_LOG_LEVEL}"
   fi
 }
+
+function _check_spam_prefix() {
+  # This check should be independent of ENABLE_POP3 and ENABLE_IMAP
+  if _env_var_expect_zero_or_one MOVE_SPAM_TO_JUNK \
+  && [[ ${MOVE_SPAM_TO_JUNK} -eq 0 ]] \
+  && [[ -z ${SPAM_SUBJECT} ]]; then
+    _log 'warn' "'MOVE_SPAM_TO_JUNK=0' and 'SPAM_SUBJECT' is empty - make sure this is intended: spam e-mails might not be immediately recognizable in this configuration"
+  fi
+}