diff --git a/src/tools/msvc/gendef.pl b/src/tools/msvc/gendef.pl
index 8ccaab35519..04b0bbe6c79 100644
--- a/src/tools/msvc/gendef.pl
+++ b/src/tools/msvc/gendef.pl
@@ -29,7 +29,7 @@ sub dumpsyms
 sub extract_syms
 {
 	my ($symfile, $def) = @_;
-	open(F, "<$symfile") || die "Could not open $symfile for $_\n";
+	open(F, "<$symfile") || die "Could not open $symfile for $_: $!\n";
 	while (<F>)
 	{