diff --git a/e2e/core/viewer/viewer-content-services-component.e2e.ts b/e2e/core/viewer/viewer-content-services-component.e2e.ts
index 0dbfd9d8a4..0361605c02 100644
--- a/e2e/core/viewer/viewer-content-services-component.e2e.ts
+++ b/e2e/core/viewer/viewer-content-services-component.e2e.ts
@@ -307,6 +307,8 @@ describe('Content Services Viewer', () => {
         viewerPage.checkInfoButtonIsDisplayed();
 
         viewerPage.checkZoomInButtonIsNotDisplayed();
+        viewerPage.checkUnknownFormatIsDisplayed();
+        expect(viewerPage.getUnknownFormatMessage()).toBe('Couldn\'t load preview. Unknown format.');
 
         viewerPage.clickCloseButton();
     });
diff --git a/e2e/pages/adf/viewerPage.ts b/e2e/pages/adf/viewerPage.ts
index 6666141db4..233f68ec04 100644
--- a/e2e/pages/adf/viewerPage.ts
+++ b/e2e/pages/adf/viewerPage.ts
@@ -100,6 +100,7 @@ export class ViewerPage {
 
     showTabWithIconSwitch = element(by.id('adf-tab-with-icon'));
     showTabWithIconAndLabelSwitch = element(by.id('adf-icon-and-label-tab'));
+    unknownFormat = element(by.css(`adf-viewer-unknown-format .adf-viewer__unknown-format-view`));
 
     checkCodeViewerIsDisplayed() {
         return BrowserVisibility.waitUntilElementIsVisible(this.codeViewer);
@@ -667,4 +668,13 @@ export class ViewerPage {
         const tab = element(by.css(`div[id="mat-tab-label-1-${index}"] div[class="mat-tab-label-content"] mat-icon`));
         return BrowserActions.getText(tab);
     }
+
+    checkUnknownFormatIsDisplayed() {
+        return BrowserVisibility.waitUntilElementIsVisible(this.unknownFormat);
+    }
+
+    getUnknownFormatMessage() {
+        const unknownFormatLabel = this.unknownFormat.element(by.css(`.label`));
+        return BrowserActions.getText(unknownFormatLabel);
+    }
 }