diff --git a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
index 60df28f4f29..bd2f3896c73 100644
--- a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
+++ b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
@@ -163,7 +163,7 @@ class AttachmentViewer extends Component {
         const image = refs[`image_${this.attachmentViewer.attachment.id}`];
         if (
             this.attachmentViewer.attachment.fileType === 'image' &&
-            !image.complete
+            (!image || !image.complete)
         ) {
             this.attachmentViewer.update({ isImageLoading: true });
         }