diff --git a/payload_consumer/postinstall_runner_action.cc b/payload_consumer/postinstall_runner_action.cc
index e489dfc..a72462a 100644
--- a/payload_consumer/postinstall_runner_action.cc
+++ b/payload_consumer/postinstall_runner_action.cc
@@ -91,9 +91,17 @@
   fs_mount_dir_ = temp_dir.value();
 #endif  // __ANDROID__
   CHECK(!fs_mount_dir_.empty());
+  EnsureUnmounted();
   LOG(INFO) << "postinstall mount point: " << fs_mount_dir_;
 }
 
+void PostinstallRunnerAction::EnsureUnmounted() {
+  if (utils::IsMountpoint(fs_mount_dir_)) {
+    LOG(INFO) << "Found previously mounted filesystem at " << fs_mount_dir_;
+    utils::UnmountFilesystem(fs_mount_dir_);
+  }
+}
+
 void PostinstallRunnerAction::PerformAction() {
   CHECK(HasInputObject());
   CHECK(boot_control_);
@@ -167,10 +175,7 @@
   }
   // Double check that the fs_mount_dir is not busy with a previous mounted
   // filesystem from a previous crashed postinstall step.
-  if (utils::IsMountpoint(fs_mount_dir_)) {
-    LOG(INFO) << "Found previously mounted filesystem at " << fs_mount_dir_;
-    utils::UnmountFilesystem(fs_mount_dir_);
-  }
+  EnsureUnmounted();
 
 #ifdef __ANDROID__
   // In Chromium OS, the postinstall step is allowed to write to the block
diff --git a/payload_consumer/postinstall_runner_action.h b/payload_consumer/postinstall_runner_action.h
index 41be201..66721af 100644
--- a/payload_consumer/postinstall_runner_action.h
+++ b/payload_consumer/postinstall_runner_action.h
@@ -70,6 +70,7 @@
 
   // exposed for testing purposes only
   void SetMountDir(std::string dir) { fs_mount_dir_ = std::move(dir); }
+  void EnsureUnmounted();
 
   void PerformPartitionPostinstall();
   [[nodiscard]] bool MountPartition(