diff --git a/src/lib-sieve/plugins/include/ext-include-binary.c b/src/lib-sieve/plugins/include/ext-include-binary.c
index 3711c30ff33db18a10afd6e4cb9f782828ef5777..11c1faaf8a5cb7f0b9d682f12fb21e12866d35aa 100644
--- a/src/lib-sieve/plugins/include/ext-include-binary.c
+++ b/src/lib-sieve/plugins/include/ext-include-binary.c
@@ -252,6 +252,12 @@ static bool ext_include_binary_open
 	sieve_size_t offset;
 
 	sblock = sieve_binary_extension_get_block(sbin, ext);
+	if (sblock == NULL) {
+		e_error(svinst->event,
+			"include: failed to load dependency block of binary %s",
+			sieve_binary_path(sbin));
+		return FALSE;
+	}
 	block_id = sieve_binary_block_get_id(sblock);
 
 	offset = 0;