diff --git a/frontend/src/lib/document/viewer/usePdfRenderer.svelte.test.ts b/frontend/src/lib/document/viewer/usePdfRenderer.svelte.test.ts
index 94b2046d..5cbbed2a 100644
--- a/frontend/src/lib/document/viewer/usePdfRenderer.svelte.test.ts
+++ b/frontend/src/lib/document/viewer/usePdfRenderer.svelte.test.ts
@@ -277,7 +277,7 @@ describe('createPdfRenderer', () => {
 		expect(r.error).toBeNull();
 	});
 
-	it('loadDocument sets error and loading=false when getDocument().promise rejects', async () => {
+	it('loadDocument sets a localized error (not the raw pdf.js message) when getDocument rejects', async () => {
 		const failingLib = {
 			GlobalWorkerOptions: { workerSrc: '' },
 			getDocument: vi.fn().mockReturnValue({
@@ -294,6 +294,7 @@ describe('createPdfRenderer', () => {
 		await r.init();
 		await r.loadDocument('/bad/path');
 		expect(r.loading).toBe(false);
-		expect(r.error).toBe('PDF not found');
+		expect(r.error).toBe(m.doc_render_failed());
+		expect(r.error).not.toContain('PDF not found');
 	});
 });
diff --git a/frontend/src/lib/document/viewer/usePdfRenderer.svelte.ts b/frontend/src/lib/document/viewer/usePdfRenderer.svelte.ts
index 1e169969..99724cf1 100644
--- a/frontend/src/lib/document/viewer/usePdfRenderer.svelte.ts
+++ b/frontend/src/lib/document/viewer/usePdfRenderer.svelte.ts
@@ -55,8 +55,10 @@ export function createPdfRenderer(libLoader: LibLoader = defaultLibLoader) {
 			const doc = await loadingTask.promise;
 			pdfDoc = doc;
 			totalPages = doc.numPages;
-		} catch (e) {
-			error = e instanceof Error ? e.message : 'Failed to load PDF';
+		} catch {
+			// Never surface the raw pdf.js message — show a localized failure
+			// that routes into the viewer's error UI (message + download link).
+			error = m.doc_render_failed();
 		} finally {
 			loading = false;
 		}