diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2106256..a15de23 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 
 #### Fixed
 - Fixed cloning of gitflow
+- Fixed pidof issue on QUEMU by replacing it with pgrep [#854](https://github.com/cytopia/devilbox/issues/854)
 
 #### Changed
 - Changed PHP 5.2 and PHP 5.3 base images to Debian stretch
diff --git a/Dockerfiles/prod/data/postfix.sh b/Dockerfiles/prod/data/postfix.sh
index 694db2a..03f8d04 100755
--- a/Dockerfiles/prod/data/postfix.sh
+++ b/Dockerfiles/prod/data/postfix.sh
@@ -29,15 +29,15 @@ MAILPID="/var/spool/postfix/pid/master.pid"
 ###
 ### Sanity checks
 ###
-if ! command -v pidof >/dev/null 2>&1; then
-	echo "pidof is required for cleaning up tail command."
+if ! command -v pgrep >/dev/null 2>&1; then
+	echo "pgrep is required for cleaning up tail command."
 	exit 1
 fi
 
 # Give rsyslogd some time to start up
 sleep 2
 
-if ! pidof rsyslogd >/dev/null 2>&1; then
+if ! pgrep rsyslogd >/dev/null 2>&1; then
 	echo "rsyslogd is not running, but required for mail logging."
 	exit 1
 fi