diff --git a/app/server/core/__tests__/repository-mutex.test.ts b/app/server/core/__tests__/repository-mutex.test.ts
new file mode 100644
index 00000000..623881e0
--- /dev/null
+++ b/app/server/core/__tests__/repository-mutex.test.ts
@@ -0,0 +1,38 @@
+import { test, describe, expect } from "bun:test";
+import { repoMutex } from "../repository-mutex";
+
+describe("RepositoryMutex", () => {
+	test("should prioritize waiting exclusive locks over new shared locks", async () => {
+		const repoId = "test-repo";
+		const results: string[] = [];
+
+		const releaseShared1 = await repoMutex.acquireShared(repoId, "backup-1");
+		results.push("acquired-shared-1");
+
+		const exclusivePromise = repoMutex.acquireExclusive(repoId, "unlock").then((release) => {
+			results.push("acquired-exclusive");
+			return release;
+		});
+
+		const shared2Promise = repoMutex.acquireShared(repoId, "backup-2").then((release) => {
+			results.push("acquired-shared-2");
+			return release;
+		});
+
+		await new Promise((resolve) => setTimeout(resolve, 50));
+
+		expect(results).toEqual(["acquired-shared-1"]);
+
+		releaseShared1();
+
+		const releaseExclusive = await exclusivePromise;
+		expect(results).toEqual(["acquired-shared-1", "acquired-exclusive"]);
+
+		releaseExclusive();
+
+		const releaseShared2 = await shared2Promise;
+		expect(results).toEqual(["acquired-shared-1", "acquired-exclusive", "acquired-shared-2"]);
+
+		releaseShared2();
+	});
+});
diff --git a/app/server/core/repository-mutex.ts b/app/server/core/repository-mutex.ts
index 4717c882..a1bb5ad4 100644
--- a/app/server/core/repository-mutex.ts
+++ b/app/server/core/repository-mutex.ts
@@ -49,7 +49,9 @@ class RepositoryMutex {
 	async acquireShared(repositoryId: string, operation: string): Promise<() => void> {
 		const state = this.getOrCreateState(repositoryId);
 
-		if (!state.exclusiveHolder) {
+		const hasExclusiveInQueue = state.waitQueue.some((item) => item.type === "exclusive");
+
+		if (!state.exclusiveHolder && !hasExclusiveInQueue) {
 			const lockId = this.generateLockId();
 			state.sharedHolders.set(lockId, {
 				id: lockId,
@@ -60,7 +62,7 @@ class RepositoryMutex {
 		}
 
 		logger.debug(
-			`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation} (exclusive held by: ${state.exclusiveHolder.operation})`,
+			`[Mutex] Waiting for shared lock on repo ${repositoryId}: ${operation} (exclusive held by: ${state.exclusiveHolder?.operation ?? "none"}, queue: ${state.waitQueue.length})`,
 		);
 		const lockId = await new Promise<string>((resolve) => {
 			state.waitQueue.push({ type: "shared", operation, resolve });
diff --git a/app/server/modules/backups/__tests__/backups.service.test.ts b/app/server/modules/backups/__tests__/backups.service.test.ts
index 4381a0cd..75933fc1 100644
--- a/app/server/modules/backups/__tests__/backups.service.test.ts
+++ b/app/server/modules/backups/__tests__/backups.service.test.ts
@@ -4,6 +4,7 @@ import { createTestVolume } from "~/test/helpers/volume";
 import { createTestBackupSchedule } from "~/test/helpers/backup";
 import { createTestRepository } from "~/test/helpers/repository";
 import { generateBackupOutput } from "~/test/helpers/restic";
+import { faker } from "@faker-js/faker";
 import * as spawnModule from "~/server/utils/spawn";
 
 const resticBackupMock = mock(() => Promise.resolve({ exitCode: 0, stdout: "", stderr: "" }));
@@ -150,3 +151,26 @@ describe("execute backup", () => {
 		expect(updatedSchedule.lastBackupStatus).toBe("error");
 	});
 });
+
+describe("getSchedulesToExecute", () => {
+	test("should return schedules with NULL lastBackupStatus", async () => {
+		// arrange
+		const volume = await createTestVolume();
+		const repository = await createTestRepository();
+
+		const schedule = await createTestBackupSchedule({
+			volumeId: volume.id,
+			repositoryId: repository.id,
+			enabled: true,
+			cronExpression: "* * * * *",
+			lastBackupStatus: null,
+			nextBackupAt: faker.date.past().getTime(),
+		});
+
+		// act
+		const schedulesToExecute = await backupsService.getSchedulesToExecute();
+
+		// assert
+		expect(schedulesToExecute).toContain(schedule.id);
+	});
+});
diff --git a/app/server/modules/backups/backups.service.ts b/app/server/modules/backups/backups.service.ts
index a9672758..1ff51247 100644
--- a/app/server/modules/backups/backups.service.ts
+++ b/app/server/modules/backups/backups.service.ts
@@ -1,4 +1,4 @@
-import { and, asc, eq, ne } from "drizzle-orm";
+import { and, asc, eq, isNull, ne, or } from "drizzle-orm";
 import cron from "node-cron";
 import { CronExpressionParser } from "cron-parser";
 import { NotFoundError, BadRequestError, ConflictError } from "http-errors-enhanced";
@@ -393,7 +393,10 @@ const executeBackup = async (scheduleId: number, manual = false) => {
 const getSchedulesToExecute = async () => {
 	const now = Date.now();
 	const schedules = await db.query.backupSchedulesTable.findMany({
-		where: and(eq(backupSchedulesTable.enabled, true), ne(backupSchedulesTable.lastBackupStatus, "in_progress")),
+		where: and(
+			eq(backupSchedulesTable.enabled, true),
+			or(ne(backupSchedulesTable.lastBackupStatus, "in_progress"), isNull(backupSchedulesTable.lastBackupStatus)),
+		),
 	});
 
 	const schedulesToRun: number[] = [];