diff --git a/libdiscover/backends/FlatpakBackend/FlatpakBackend.h b/libdiscover/backends/FlatpakBackend/FlatpakBackend.h
--- a/libdiscover/backends/FlatpakBackend/FlatpakBackend.h
+++ b/libdiscover/backends/FlatpakBackend/FlatpakBackend.h
@@ -50,7 +50,7 @@
     ResultsStream * search(const AbstractResourcesBackend::Filters & search) override;
     ResultsStream * findResourceByPackageName(const QUrl &search) override;
     QList<FlatpakResource*> resources() const { return m_resources.values(); }
-    bool isValid() const override { return true; } // No external file dependencies that could cause runtime errors
+    bool isValid() const override;
     QList<QAction*> messageActions() const override { return m_messageActions; }
 
     FlatpakInstallation *flatpakInstallationForAppScope(FlatpakResource::Scope appScope) const;
@@ -98,7 +98,7 @@
 
     QHash<QString, FlatpakResource*> m_resources;
     StandardBackendUpdater  *m_updater;
-    FlatpakSourcesBackend *m_sources;
+    FlatpakSourcesBackend *m_sources = nullptr;
     OdrsReviewsBackend *m_reviews;
     bool m_fetching;
     QList<QAction*> m_messageActions;
diff --git a/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp b/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
--- a/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
+++ b/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
@@ -76,6 +76,9 @@
         reloadPackageList();
 
         checkForUpdates();
+
+        m_sources = new FlatpakSourcesBackend(m_flatpakInstallationSystem, m_flatpakInstallationUser, this);
+        SourcesModel::global()->addSourcesBackend(m_sources);
     }
 
     QAction* updateAction = new QAction(this);
@@ -86,9 +89,6 @@
 
     m_messageActions = QList<QAction*>() << updateAction;
 
-    m_sources = new FlatpakSourcesBackend(m_flatpakInstallationSystem, m_flatpakInstallationUser, this);
-    SourcesModel::global()->addSourcesBackend(m_sources);
-
     connect(m_reviews, &OdrsReviewsBackend::ratingsReady, this, &FlatpakBackend::announceRatingsReady);
 }
 
@@ -99,6 +99,11 @@
     g_object_unref(m_cancellable);
 }
 
+bool FlatpakBackend::isValid() const
+{
+    return m_sources && m_flatpakInstallationUser && m_flatpakInstallationSystem;
+}
+
 void FlatpakBackend::announceRatingsReady()
 {
     emitRatingsReady();