lib/PublicInbox/Import.pm | 2 ++

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index f320c58c6b575023ec94dfcd12e8cbd6910f7af4..4e3b4c55179766797b41960ea7c55bc266f210f4 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -278,10 +278,12 @@ 	my ($mime) = @_;
 
 	my $sender = '';
 	my $from = $mime->header('From');
+	$from ||= '';
 	my ($email) = PublicInbox::Address::emails($from);
 	my ($name) = PublicInbox::Address::names($from);
 	if (!defined($name) || !defined($email)) {
 		$sender = $mime->header('Sender');
+		$sender ||= '';
 		if (!defined($name)) {
 			($name) = PublicInbox::Address::names($sender);
 		}