diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index f1d76e7..c3b2f78 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -2215,6 +2215,8 @@
 TEST_F(SnapshotUpdateTest, CancelOnTargetSlot) {
     AddOperationForPartitions();
 
+    ASSERT_TRUE(UnmapAll());
+
     // Execute the update from B->A.
     test_device->set_slot_suffix("_b");
     ASSERT_TRUE(sm->BeginUpdate());