diff --git a/sympa/recipe/sympa_fix_personalization.recipe b/sympa/recipe/sympa_fix_personalization.recipe
index dbe43dd..a40d9aa 100644
--- a/sympa/recipe/sympa_fix_personalization.recipe
+++ b/sympa/recipe/sympa_fix_personalization.recipe
@@ -22,7 +22,7 @@ function fix_personalization {
 
 function patch_message_pm {
 	if [[ -f $MESSAGE_PM ]]; then
-		if grep -q '^.*qw/subject x-originating-ip message-id date x-original-to x-original-from.*$' "$MESSAGE_PM"; then
+		if ! grep -q '^.*qw/subject x-originating-ip message-id date x-original-to x-original-from.*$' "$MESSAGE_PM"; then
 			/opt/miaou-bash/tools/append_or_replace '^.*qw/subject x-originating-ip message-id date x-original-to.*$' '        qw/subject x-originating-ip message-id date x-original-to x-original-from from to thread-topic content-type/' "$MESSAGE_PM"
 			FOUND=true
 		else