diff --git a/src/test/pmempool_sync/TEST24 b/src/test/pmempool_sync/TEST24
index dbbfecc5798..e70d3e2ef00 100755
--- a/src/test/pmempool_sync/TEST24
+++ b/src/test/pmempool_sync/TEST24
@@ -61,7 +61,7 @@ expect_normal_exit $PMEMPOOL$EXESUFFIX sync $POOLSET1 >> $LOG_TEMP
 dump_pool_info $POOLSET1 >> $LOG_TEMP
 
 # Exclude error and warn messages printed out on the stderr by PMDK in debug
-fgrep -v "*ERROR*" $LOG_TEMP | fgrep -v "*WARN*" | fgrep -v "*WARN*" > $LOG
+fgrep -v "*ERROR*" $LOG_TEMP | fgrep -v "*WARN*" > $LOG
 rm $LOG_TEMP
 
 check
diff --git a/src/test/pmempool_transform/TEST5 b/src/test/pmempool_transform/TEST5
index 8cbf7e86b42..47541d1a92c 100755
--- a/src/test/pmempool_transform/TEST5
+++ b/src/test/pmempool_transform/TEST5
@@ -92,8 +92,8 @@ dump_pool_info $DIR/testfile01 >> $LOG_TEMP
 dump_pool_info $DIR/testfile02 >> $LOG_TEMP
 dump_pool_info $DIR/testfile10 >> $LOG_TEMP
 
-# Exclude error and warning messages printed out on the stderr by PMDK in debug
-grep -v -E "\*ERROR\*|\*WARN\*" $LOG_TEMP > $LOG
+# Exclude error and warn messages printed out on the stderr by PMDK in debug
+fgrep -v "*ERROR*" $LOG_TEMP | fgrep -v "*WARN*" > $LOG
 rm $LOG_TEMP
 
 check
diff --git a/src/test/pmempool_transform/TEST6 b/src/test/pmempool_transform/TEST6
index a09722b3e0d..420a5f03ab8 100755
--- a/src/test/pmempool_transform/TEST6
+++ b/src/test/pmempool_transform/TEST6
@@ -71,8 +71,8 @@ expect_abnormal_exit $PMEMPOOL$EXESUFFIX transform \
 # Check metadata by pmempool info
 dump_pool_info $POOLSET_OUT1 >> $LOG_TEMP
 
-# Exclude error and warning messages printed out on the stderr by PMDK in debug
-grep -v -E "\*ERROR\*|\*WARN\*" $LOG_TEMP > $LOG
+# Exclude error and warn messages printed out on the stderr by PMDK in debug
+fgrep -v "*ERROR*" $LOG_TEMP | fgrep -v "*WARN*" > $LOG
 rm $LOG_TEMP
 
 check