diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index 3eb70c1bdb9..86d37a56835 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -5388,16 +5388,14 @@ sub start_servers($) {
     my $mysqld_basedir= $mysqld->value('basedir');
     if ( $basedir eq $mysqld_basedir )
     {
-      if (! $opt_start_dirty)	# If dirty, keep possibly grown system db
+      if (!$opt_start_dirty)	# If dirty, keep possibly grown system db
       {
-	# Copy datadir from installed system db
-	for my $path ( "$opt_vardir", "$opt_vardir/..") {
-	  my $install_db= "$path/install.db";
-	  copytree($install_db, $datadir)
-	    if -d $install_db;
-	}
-	mtr_error("Failed to copy system db to '$datadir'")
-	  unless -d $datadir;
+        # Copy datadir from installed system db
+        my $path= ($opt_parallel == 1) ? "$opt_vardir" : "$opt_vardir/..";
+        my $install_db= "$path/install.db";
+        copytree($install_db, $datadir) if -d $install_db;
+        mtr_error("Failed to copy system db to '$datadir'")
+          unless -d $datadir;
       }
     }
     else