diff --git a/packages/web-app-media-viewer/src/App.vue b/packages/web-app-media-viewer/src/App.vue
index b23a2a412da..d2ab82de869 100644
--- a/packages/web-app-media-viewer/src/App.vue
+++ b/packages/web-app-media-viewer/src/App.vue
@@ -185,7 +185,8 @@ export default {
         x: this.thumbDimensions,
         y: this.thumbDimensions,
         // strip double quotes from etag
-        c: this.activeMediaFile.etag.substr(1, this.activeMediaFile.etag.length - 2),
+        // we have no etag, e.g. on shared with others page
+        c: this.activeMediaFile.etag?.substr(1, this.activeMediaFile.etag.length - 2),
         scalingup: 0,
         preview: 1,
         a: 1