diff --git a/src/control/signal.c b/src/control/signal.c
index 646c3b8bc044..47c9c3feb9ad 100644
--- a/src/control/signal.c
+++ b/src/control/signal.c
@@ -206,6 +206,9 @@ static dt_signal_description _signal_description[DT_SIGNAL_COUNT] = {
   { "dt-location-changed", NULL, NULL, G_TYPE_NONE, g_cclosure_marshal_generic, 1, pointer_arg, NULL,
     TRUE }, // DT_SIGNAL_LOCATION_CHANGED
 
+ { "dt-imageio-storage-export-enable", NULL, NULL, G_TYPE_NONE, g_cclosure_marshal_VOID__VOID, 0, NULL, NULL,
+    FALSE }, // DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE
+
 };
 
 static GType _signal_type;
diff --git a/src/control/signal.h b/src/control/signal.h
index 24a7d443e882..225c1cc65d1f 100644
--- a/src/control/signal.h
+++ b/src/control/signal.h
@@ -275,6 +275,11 @@ typedef enum dt_signal_t
   /* \brief This signal is raised when the user choses a new location from map (module location)*/
   DT_SIGNAL_LOCATION_CHANGED,
 
+  /** \brief This signal is raised when a storage module signalizes to enable/disable the export
+    no param, no returned value
+  */
+  DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE,
+
   /* do not touch !*/
   DT_SIGNAL_COUNT
 } dt_signal_t;
diff --git a/src/imageio/storage/imageio_storage_api.h b/src/imageio/storage/imageio_storage_api.h
index f1a56974c5a8..384a2423b3bc 100644
--- a/src/imageio/storage/imageio_storage_api.h
+++ b/src/imageio/storage/imageio_storage_api.h
@@ -91,6 +91,9 @@ OPTIONAL(void, export_dispatched, struct dt_imageio_module_storage_t *self);
 
 OPTIONAL(char *, ask_user_confirmation, struct dt_imageio_module_storage_t *self);
 
+/* ask the storage if export is currently possible */
+OPTIONAL(gboolean, export_enabled, struct dt_imageio_module_storage_t *self);
+
 #ifdef FULL_API_H
 
 #pragma GCC visibility pop
diff --git a/src/imageio/storage/piwigo.c b/src/imageio/storage/piwigo.c
index 7488bfdc664b..b7d983eafbce 100644
--- a/src/imageio/storage/piwigo.c
+++ b/src/imageio/storage/piwigo.c
@@ -600,6 +600,8 @@ static void _piwigo_authenticate(dt_storage_piwigo_gui_data_t *ui)
     _piwigo_set_status(ui, _("not authenticated, cannot reach server"), "#e07f7f");
     _piwigo_ctx_destroy(&ui->api);
   }
+
+  DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE);
 }
 
 static void _piwigo_entry_changed(GtkEntry *entry,
@@ -608,9 +610,11 @@ static void _piwigo_entry_changed(GtkEntry *entry,
   dt_storage_piwigo_gui_data_t *ui = (dt_storage_piwigo_gui_data_t *)data;
 
   _piwigo_set_status(ui, _("not authenticated"), "#e07f7f");
-    gtk_widget_set_sensitive(GTK_WIDGET(ui->album_list), FALSE);
+  gtk_widget_set_sensitive(GTK_WIDGET(ui->album_list), FALSE);
 
   if(ui->api) _piwigo_ctx_destroy(&ui->api);
+
+  DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE);
 }
 
 static void _piwigo_server_entry_changed(GtkEntry *entry,
@@ -624,6 +628,8 @@ static void _piwigo_server_entry_changed(GtkEntry *entry,
     _piwigo_ctx_destroy(&ui->api);
     gtk_widget_set_sensitive(GTK_WIDGET(ui->album_list), FALSE);
   }
+
+  DT_DEBUG_CONTROL_SIGNAL_RAISE(darktable.signals, DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE);
 }
 
 static void _piwigo_account_changed(GtkComboBox *cb,
@@ -1214,8 +1220,13 @@ static gboolean _finalize_store(gpointer user_data)
 {
   dt_storage_piwigo_gui_data_t *g = (dt_storage_piwigo_gui_data_t *)user_data;
 
-  // notify that uploads are completed to empty the lounge
+  if(g->api == NULL)
+  {
+    // not logged in, nothing to cleanup
+    return FALSE;
+  }
 
+  // notify that uploads are completed to empty the lounge
   if(!g->api->error_occured)
   {
     GList *args = NULL;
@@ -1265,6 +1276,14 @@ int store(dt_imageio_module_storage_t *self,
   dt_storage_piwigo_gui_data_t *ui = self->gui_data;
   dt_storage_piwigo_params_t *p = (dt_storage_piwigo_params_t *)sdata;
 
+  if(p->api == NULL)
+  {
+    dt_print(DT_DEBUG_ALWAYS,
+             "[imageio_storage_piwigo] not logged in to Piwigo server!\n");
+    dt_control_log(_("not logged in to Piwigo server!"));
+    return 1;
+  }
+    
   gint result = 0;
   gint skipped = 0;
 
@@ -1585,6 +1604,13 @@ gboolean supported(dt_imageio_module_storage_t *storage,
   return FALSE;
 }
 
+gboolean export_enabled(dt_imageio_module_storage_t *self)
+{
+  dt_storage_piwigo_gui_data_t *ui = self->gui_data;
+
+  return ui->api != NULL && ui->api->authenticated;
+}
+
 void free_params(dt_imageio_module_storage_t *self,
                  dt_imageio_module_data_t *params)
 {
diff --git a/src/libs/export.c b/src/libs/export.c
index a505941ec0f5..35ca22716807 100644
--- a/src/libs/export.c
+++ b/src/libs/export.c
@@ -196,8 +196,17 @@ void gui_update(dt_lib_module_t *self)
   const int storage_index =
     dt_imageio_get_index_of_storage(dt_imageio_get_storage_by_name(storage_name));
 
+  dt_imageio_module_storage_t *storage = dt_imageio_get_storage();
+
+  gboolean export_enabled = TRUE;
+  if(storage->export_enabled)
+    export_enabled = storage->export_enabled(storage);
+
   gtk_widget_set_sensitive(GTK_WIDGET(d->export_button),
-                           has_act_on && format_index != -1 && storage_index != -1);
+                           has_act_on
+                           && format_index != -1
+                           && storage_index != -1
+                           && export_enabled);
 }
 
 static void _image_selection_changed_callback(gpointer instance,
@@ -221,6 +230,12 @@ static void _mouse_over_image_callback(gpointer instance, dt_lib_module_t *self)
   dt_lib_gui_queue_update(self);
 }
 
+static void _export_enable_callback(gpointer instance,
+                                    dt_lib_module_t *self)
+{
+  dt_lib_gui_queue_update(self);
+}
+
 gboolean _is_int(double value)
 {
   return (value == (int)value);
@@ -844,12 +859,15 @@ static void set_storage_by_name(dt_lib_export_t *d,
     dt_bauhaus_combobox_set(d->format, 0);
 }
 
-static void _storage_changed(GtkWidget *widget, dt_lib_export_t *d)
+static void _storage_changed(GtkWidget *widget, dt_lib_module_t *self)
 {
+  dt_lib_export_t *d = self->data;
+
   const gchar *name = dt_bauhaus_combobox_get_text(d->storage);
-  g_signal_handlers_block_by_func(widget, _storage_changed, d);
+  g_signal_handlers_block_by_func(widget, _storage_changed, self);
   if(name) set_storage_by_name(d, name);
-  g_signal_handlers_unblock_by_func(widget, _storage_changed, d);
+  g_signal_handlers_unblock_by_func(widget, _storage_changed, self);
+  dt_lib_gui_queue_update(self);
 }
 
 static void _profile_changed(GtkWidget *widget, dt_lib_export_t *d)
@@ -1173,7 +1191,7 @@ void gui_init(dt_lib_module_t *self)
   DT_DEBUG_CONTROL_SIGNAL_CONNECT(darktable.signals, DT_SIGNAL_IMAGEIO_STORAGE_CHANGE,
                             G_CALLBACK(_on_storage_list_changed), self);
   g_signal_connect(G_OBJECT(d->storage), "value-changed",
-                   G_CALLBACK(_storage_changed), (gpointer)d);
+                   G_CALLBACK(_storage_changed), self);
 
   label = dt_ui_section_label_new(C_("section", "format options"));
   gtk_box_pack_start(GTK_BOX(self->widget), label, FALSE, TRUE, 0);
@@ -1494,6 +1512,8 @@ void gui_init(dt_lib_module_t *self)
                             G_CALLBACK(_mouse_over_image_callback), self);
   DT_DEBUG_CONTROL_SIGNAL_CONNECT(darktable.signals, DT_SIGNAL_COLLECTION_CHANGED,
                             G_CALLBACK(_collection_updated_callback), self);
+  DT_DEBUG_CONTROL_SIGNAL_CONNECT(darktable.signals, DT_SIGNAL_IMAGEIO_STORAGE_EXPORT_ENABLE,
+                            G_CALLBACK(_export_enable_callback), self);
 }
 
 void gui_cleanup(dt_lib_module_t *self)