diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index 3f19c828b1..1461b51b69 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -411,7 +411,9 @@ class EbookViewer(MainWindow):
         if msg:
             self.loading_overlay(msg)
         else:
-            performance_monitor('loading finished')
+            if not hasattr(self, 'initial_loading_performace_reported'):
+                performance_monitor('loading finished')
+                self.initial_loading_performace_reported = True
             self.loading_overlay.hide()
 
     def show_error(self, title, msg, details):