@@ -, +, @@ invalid ISBN-13 Click on Upload file, then Stage to import. --- C4/Koha.pm | 1 + 1 file changed, 1 insertion(+) --- a/C4/Koha.pm +++ a/C4/Koha.pm @@ -1680,6 +1680,7 @@ sub NormalizeISBN { elsif ( $format eq 'ISBN-13' ) { $isbn = $isbn->as_isbn13(); } + return unless $isbn; if ($strip_hyphens) { $string = $isbn->as_string( [] ); --