diff --git a/src/app/crash/backup_observer.cpp b/src/app/crash/backup_observer.cpp
index 5a4f4f17b..5ab1710c6 100644
--- a/src/app/crash/backup_observer.cpp
+++ b/src/app/crash/backup_observer.cpp
@@ -50,7 +50,7 @@ void BackupObserver::onAddDocument(doc::Document* document)
 {
   TRACE("DataRecovery: Observe document %p\n", document);
   base::scoped_lock hold(m_mutex);
-  m_documents.push_back(document);
+  m_documents.push_back(static_cast<app::Document*>(document));
 }
 
 void BackupObserver::onRemoveDocument(doc::Document* document)
@@ -58,7 +58,7 @@ void BackupObserver::onRemoveDocument(doc::Document* document)
   TRACE("DataRecovery:: Remove document %p\n", document);
   {
     base::scoped_lock hold(m_mutex);
-    base::remove_from_container(m_documents, document);
+    base::remove_from_container(m_documents, static_cast<app::Document*>(document));
   }
   m_session->removeDocument(static_cast<app::Document*>(document));
 }
@@ -78,9 +78,10 @@ void BackupObserver::backgroundThread()
       base::Chrono chrono;
       bool somethingLocked = false;
 
-      for (doc::Document* doc : m_documents) {
+      for (app::Document* doc : m_documents) {
         try {
-          m_session->saveDocumentChanges(static_cast<app::Document*>(doc));
+          if (doc->needsBackup())
+            m_session->saveDocumentChanges(doc);
         }
         catch (const std::exception&) {
           TRACE("DataRecovery: Document '%d' is locked\n", doc->id());
diff --git a/src/app/crash/backup_observer.h b/src/app/crash/backup_observer.h
index faa5e6e3b..7f0f4d90a 100644
--- a/src/app/crash/backup_observer.h
+++ b/src/app/crash/backup_observer.h
@@ -22,6 +22,7 @@ namespace doc {
 }
 
 namespace app {
+class Document;
 namespace crash {
   class Session;
 
@@ -43,7 +44,7 @@ namespace crash {
     Session* m_session;
     base::mutex m_mutex;
     doc::Context* m_ctx;
-    std::vector<doc::Document*> m_documents;
+    std::vector<app::Document*> m_documents;
     bool m_done;
     base::thread m_thread;
   };
diff --git a/src/app/document.cpp b/src/app/document.cpp
index 898515713..084ceb4be 100644
--- a/src/app/document.cpp
+++ b/src/app/document.cpp
@@ -200,6 +200,13 @@ void Document::impossibleToBackToSavedState()
   m_undo->impossibleToBackToSavedState();
 }
 
+bool Document::needsBackup() const
+{
+  // If the undo history isn't empty, the user has modified the
+  // document, so we needs to backup those changes.
+  return m_undo->canUndo() || m_undo->canRedo();
+}
+
 //////////////////////////////////////////////////////////////////////
 // Loaded options from file
 
diff --git a/src/app/document.h b/src/app/document.h
index c6011ce46..aa5383203 100644
--- a/src/app/document.h
+++ b/src/app/document.h
@@ -100,6 +100,11 @@ namespace app {
     // back to the saved state using the UndoHistory.
     void impossibleToBackToSavedState();
 
+    // Returns true if it does make sense to create a backup in this
+    // document. For example, it doesn't make sense to create a backup
+    // for an unmodified document.
+    bool needsBackup() const;
+
     //////////////////////////////////////////////////////////////////////
     // Loaded options from file