diff --git a/scripts/check-format.sh b/scripts/check-format.sh
index 1ad2a1bb88a3d970fb17c9df4ba2dc4c9b6aebe9..db6c681e9dfd515db91e8ed78da252ef06536769 100755
--- a/scripts/check-format.sh
+++ b/scripts/check-format.sh
@@ -69,6 +69,16 @@ cl-format-apply() {
     ${CLANG_FORMAT} -i $1
 }
 
+ensure-one-newline()
+{
+    # first command adds a newline at the end of the file if there might be none
+    # -> clang-format-13 does not add them and warnings e.g. on MacOS are triggered by them
+    sed -i -e '$a\' $1
+    # second command removes multiple newlines at the end of a file so that there is only one left
+    # -> clang-format-13 does not do that, but complains about it
+    sed -i -e :a -e '/^\n*$/{$d;N;ba' -e '}' $1
+}
+
 cl-format-check() {
     local I=$1
     local COLOR=$2
@@ -197,6 +207,7 @@ if [[ $NUMPROCS -lt 2 ]]; then
         RET=$?
         ((NUMFAILS+=RET))
         if [ $FORMAT ]; then
+            ensure-one-newline $i
             cl-format-apply $i
         fi
     done
@@ -218,6 +229,7 @@ else
         fi
         ((NUMFAILS+=RET))
         if [ $FORMAT ]; then
+            ensure-one-newline $i
             cl-format-apply $i
         fi ) &
         while [[ $(jobs -r -p | wc -l) -ge $NUMPROCS ]];do