diff --git a/lib/KorAP/Field/MultiTermTokenStream.pm b/lib/KorAP/Field/MultiTermTokenStream.pm
index 47524ab..317c59e 100644
--- a/lib/KorAP/Field/MultiTermTokenStream.pm
+++ b/lib/KorAP/Field/MultiTermTokenStream.pm
@@ -22,6 +22,7 @@
 sub pos {
   my $self = shift;
   my $pos = shift;
+  return unless defined $pos;
   return $self->{mtt}->[$pos];
 };
 
diff --git a/lib/KorAP/Tokenizer.pm b/lib/KorAP/Tokenizer.pm
index 9ff8c51..7cecc2b 100644
--- a/lib/KorAP/Tokenizer.pm
+++ b/lib/KorAP/Tokenizer.pm
@@ -46,6 +46,12 @@
   # Create new token stream
   my $mtts = KorAP::Field::MultiTermTokenStream->new;
   my $path = $self->path . lc($self->foundry) . '/' . lc($self->layer) . '.xml';
+
+  unless (-e $path) {
+    $self->log->warn('Unable to load base tokenization: ' . $path);
+    return;
+  };
+
   my $file = b($path)->slurp;
 #  my $tokens = Mojo::DOM->new($file);
 #  $tokens->xml(1);