diff --git a/app/dockerdwrapperwithcompose.c b/app/dockerdwrapperwithcompose.c
index 5c5c27d..2b32d90 100644
--- a/app/dockerdwrapperwithcompose.c
+++ b/app/dockerdwrapperwithcompose.c
@@ -743,10 +743,12 @@ static void
 sd_card_callback(const char *sd_card_area, void *app_state_void_ptr)
 {
   struct app_state *app_state = app_state_void_ptr;
-  if (!sd_card_area)
+  const bool using_sd_card = is_parameter_yes(PARAM_SD_CARD_SUPPORT);
+  if (using_sd_card && !sd_card_area)
     stop_dockerd(); // Block here until dockerd has stopped using the SD card.
   app_state->sd_card_area = sd_card_area ? strdup(sd_card_area) : NULL;
-  g_main_loop_quit(loop); // Trigger a restart of dockerd from main()
+  if (using_sd_card)
+    g_main_loop_quit(loop); // Trigger a restart of dockerd from main()
 }
 
 // Stop the application and start it from an SSH prompt with
diff --git a/app/sd_disk_storage.h b/app/sd_disk_storage.h
index 54dbb66..ff65019 100644
--- a/app/sd_disk_storage.h
+++ b/app/sd_disk_storage.h
@@ -2,8 +2,10 @@
 
 typedef void (*SdDiskCallback)(const char *area_path, void *user_data);
 
-// Call sd_disk_callback with a path to the SD card when it has become available
-// and with NULL when it is about to be unmounted.
+// Call sd_disk_callback with a path to the SD card when it has become
+// available. Call sd_disk_callback with NULL when it is about to be unmounted.
+// Unmounting will fail if the SD card area contains open files when the
+// callback returns.
 struct sd_disk_storage *sd_disk_storage_init(SdDiskCallback sd_disk_callback,
                                              void *user_data);