diff --git a/sbin/dump/main.c b/sbin/dump/main.c
index 127b5ca33f9..a7123fb96de 100644
--- a/sbin/dump/main.c
+++ b/sbin/dump/main.c
@@ -433,6 +433,7 @@ main(int argc, char *argv[])
 		msgtail("to %s\n", tape);
 
 	sync();
+	sblock = NULL;
 	if ((ret = sbget(diskfd, &sblock, -1)) != 0) {
 		switch (ret) {
 		case ENOENT: