diff --git a/app/server/modules/notifications/notifications.service.ts b/app/server/modules/notifications/notifications.service.ts
index 2d4d9b3a..ae553ebd 100644
--- a/app/server/modules/notifications/notifications.service.ts
+++ b/app/server/modules/notifications/notifications.service.ts
@@ -6,7 +6,7 @@ import {
 	backupScheduleNotificationsTable,
 	type NotificationDestination,
 } from "../../db/schema";
-import { logger } from "@zerobyte/core/node";
+import { logger, sanitizeSensitiveData } from "@zerobyte/core/node";
 import { isAllowedWebhookUrl } from "@zerobyte/core/backup-hooks";
 import { sendNotification } from "../../utils/shoutrrr";
 import { formatDuration } from "~/utils/utils";
@@ -20,6 +20,12 @@ import { formatBytes } from "~/utils/format-bytes";
 import { decryptNotificationConfig, encryptNotificationConfig } from "./notification-config-secrets";
 import { serverEvents } from "~/server/core/events";
 
+const MAX_DELIVERY_ERROR_LENGTH = 2048;
+
+const formatDeliveryError = (error?: string) => {
+	return sanitizeSensitiveData(error ?? "Unknown error").slice(0, MAX_DELIVERY_ERROR_LENGTH);
+};
+
 const getCustomShoutrrrWebhookUrl = (shoutrrrUrl: string) => {
 	if (!URL.canParse(shoutrrrUrl)) {
 		return null;
@@ -195,7 +201,7 @@ const updateDeliveryStatus = async (destinationId: number, result: { success: bo
 		.set({
 			status: result.success ? "healthy" : "error",
 			lastChecked: Date.now(),
-			lastError: result.success ? null : (result.error ?? "Unknown error"),
+			lastError: result.success ? null : formatDeliveryError(result.error),
 			updatedAt: Date.now(),
 		})
 		.where(eq(notificationDestinationsTable.id, destinationId))
diff --git a/app/server/utils/shoutrrr.ts b/app/server/utils/shoutrrr.ts
index 336ba7b6..e1ba525d 100644
--- a/app/server/utils/shoutrrr.ts
+++ b/app/server/utils/shoutrrr.ts
@@ -1,5 +1,4 @@
-import { safeExec } from "@zerobyte/core/node";
-import { logger } from "@zerobyte/core/node";
+import { logger, safeExec, sanitizeSensitiveData } from "@zerobyte/core/node";
 import { toMessage } from "./errors";
 
 interface SendNotificationParams {
@@ -23,7 +22,7 @@ export async function sendNotification(params: SendNotificationParams) {
 			return { success: true };
 		}
 
-		const errorMessage = result.stderr || result.stdout || "Unknown error";
+		const errorMessage = sanitizeSensitiveData(result.stderr || result.stdout || "Unknown error");
 		logger.error(`Failed to send notification: ${errorMessage}`);
 		return {
 			success: false,
diff --git a/e2e/0004-mirror-sync.spec.ts b/e2e/0004-mirror-sync.spec.ts
index 382d2061..18caddba 100644
--- a/e2e/0004-mirror-sync.spec.ts
+++ b/e2e/0004-mirror-sync.spec.ts
@@ -12,10 +12,27 @@ type RepositorySummary = {
 	shortId: string;
 };
 
+type MirrorAssignmentSummary = {
+	repositoryId: string;
+	lastCopyStatus: "success" | "error" | "in_progress" | null;
+};
+
+type MirrorSyncStatus = {
+	sourceCount: number;
+	mirrorCount: number;
+	missingSnapshots: unknown[];
+};
+
 function getRunId(testInfo: TestInfo) {
 	return `${testInfo.parallelIndex}-${testInfo.retry}-${randomUUID().slice(0, 8)}`;
 }
 
+function getBackupShortId(backupPageUrl: string) {
+	const backupShortId = new URL(backupPageUrl).pathname.split("/").filter(Boolean).at(-1);
+	expect(backupShortId).toBeTruthy();
+	return backupShortId!;
+}
+
 function getWorkerTestDataPath() {
 	fs.mkdirSync(testDataPath, { recursive: true });
 	return testDataPath;
@@ -82,6 +99,25 @@ async function createBackupJob(page: Page, backupName: string, volumeName: strin
 	await expect(page.getByText("Backup job created successfully")).toBeVisible();
 }
 
+async function waitForMirrorSyncComplete(page: Page, backupShortId: string, mirrorRepoShortId: string) {
+	await expect(async () => {
+		const mirrorsResponse = await page.request.get(`/api/v1/backups/${backupShortId}/mirrors`);
+		expect(mirrorsResponse.ok()).toBe(true);
+		const mirrors = (await mirrorsResponse.json()) as MirrorAssignmentSummary[];
+		const mirror = mirrors.find((entry) => entry.repositoryId === mirrorRepoShortId);
+		expect(mirror?.lastCopyStatus).toBe("success");
+
+		const statusResponse = await page.request.get(
+			`/api/v1/backups/${backupShortId}/mirrors/${mirrorRepoShortId}/status`,
+		);
+		expect(statusResponse.ok()).toBe(true);
+		const status = (await statusResponse.json()) as MirrorSyncStatus;
+		expect(status.sourceCount).toBe(1);
+		expect(status.mirrorCount).toBe(1);
+		expect(status.missingSnapshots).toHaveLength(0);
+	}).toPass({ timeout: 30000 });
+}
+
 test("can sync missing snapshots to a mirror repository", async ({ page }, testInfo) => {
 	const runId = getRunId(testInfo);
 	const volumeName = `Volume-${runId}`;
@@ -104,6 +140,7 @@ test("can sync missing snapshots to a mirror repository", async ({ page }, testI
 	await createBackupJob(page, backupName, volumeName, primaryRepoName);
 
 	const backupPageUrl = page.url();
+	const backupShortId = getBackupShortId(backupPageUrl);
 	const primaryRepoShortId = await getRepositoryShortId(page, primaryRepoName);
 	const mirrorRepoShortId = await getRepositoryShortId(page, mirrorRepoName);
 
@@ -142,20 +179,17 @@ test("can sync missing snapshots to a mirror repository", async ({ page }, testI
 	const syncButton = syncDialog.getByRole("button", { name: "Sync 1 snapshots" });
 	await expect(syncButton).toBeEnabled();
 
-	// Click sync button and wait for the mirror repository to contain the snapshot.
+	// Click sync and wait on the mirror status that backs this dialog and row.
 	await syncButton.click();
-	await gotoAndWaitForAppReady(page, `/repositories/${mirrorRepoShortId}`);
-	await page.getByRole("tab", { name: "Snapshots" }).click();
-	await expect(page.getByText("Backup snapshots stored in this repository.")).toBeVisible();
-	await expect(async () => {
-		await page.getByRole("button", { name: "Refresh" }).click();
-		await expect(page.getByRole("checkbox", { name: /Select snapshot/ })).toHaveCount(1);
-	}).toPass({ timeout: 30000 });
+	await waitForMirrorSyncComplete(page, backupShortId, mirrorRepoShortId);
 	await gotoAndWaitForAppReady(page, backupPageUrl);
 
 	// Open sync dialog again and verify all snapshots are synced
-	await mirrorRow.getByRole("button").first().click();
-	await expect(syncDialog.getByRole("heading", { name: "Sync snapshots" })).toBeVisible();
+	await expect(async () => {
+		await expect(mirrorRow).toBeVisible();
+		await mirrorRow.getByRole("button").first().click();
+		await expect(syncDialog.getByRole("heading", { name: "Sync snapshots" })).toBeVisible();
+	}).toPass({ timeout: 15000 });
 	await expect(syncDialog.getByText(/All 1 snapshots are already synced/)).toBeVisible({ timeout: 15000 });
 	await syncDialog.getByRole("button", { name: "Cancel" }).click();
 
diff --git a/packages/core/src/backup-hooks/__tests__/hooks.test.ts b/packages/core/src/backup-hooks/__tests__/hooks.test.ts
index 54b3870f..bbf65209 100644
--- a/packages/core/src/backup-hooks/__tests__/hooks.test.ts
+++ b/packages/core/src/backup-hooks/__tests__/hooks.test.ts
@@ -125,6 +125,33 @@ test("sends warning details to the post-backup webhook for a non-zero completed
 	});
 });
 
+test("sends warning details to the post-backup webhook for a zero-exit completed backup with warnings", async () => {
+	let postBody: WebhookBody | undefined;
+
+	server.use(
+		http.post("http://localhost:8080/post", async ({ request }) => {
+			postBody = (await request.json()) as WebhookBody;
+			return new HttpResponse(null, { status: 204 });
+		}),
+	);
+
+	const result = await runWithHooks({
+		webhooks: {
+			pre: null,
+			post: { url: "http://localhost:8080/post" },
+		},
+		runBackup: () => completedBackup("snapshot-1", 0, "Backup was stopped by the user"),
+	});
+
+	expect(postBody).toMatchObject({ status: "warning", error: "Backup was stopped by the user" });
+	expect(result).toEqual({
+		status: "completed",
+		exitCode: 0,
+		result: "snapshot-1",
+		warningDetails: "Backup was stopped by the user",
+	});
+});
+
 test("sends error details to the post-backup webhook when the backup fails", async () => {
 	let postBody: WebhookBody | undefined;
 
diff --git a/packages/core/src/backup-hooks/index.ts b/packages/core/src/backup-hooks/index.ts
index 4533ec47..4779e340 100644
--- a/packages/core/src/backup-hooks/index.ts
+++ b/packages/core/src/backup-hooks/index.ts
@@ -96,12 +96,16 @@ const appendDetails = (primary: string | null | undefined, next: string | null |
 	return [primary, next].filter(Boolean).join("\n\n");
 };
 
-const getCompletedStatus = (exitCode: number, signal: AbortSignal): BackupWebhookStatus => {
+const getCompletedStatus = (
+	exitCode: number,
+	warningDetails: string | null,
+	signal: AbortSignal,
+): BackupWebhookStatus => {
 	if (signal.aborted) {
 		return "cancelled";
 	}
 
-	return exitCode === 0 ? "success" : "warning";
+	return exitCode === 0 && !warningDetails ? "success" : "warning";
 };
 
 const createAbortController = (timeoutMs: number, signal?: AbortSignal) => {
@@ -284,7 +288,7 @@ export const runBackupLifecycle = <TResult>({
 			Effect.map((result) => ({
 				status: "completed" as const,
 				...result,
-				hookStatus: getCompletedStatus(result.exitCode, signal),
+				hookStatus: getCompletedStatus(result.exitCode, result.warningDetails, signal),
 				hookError: signal.aborted ? formatError(signal.reason) : (result.warningDetails ?? undefined),
 			})),
 			Effect.catchAll((error) => {