diff --git a/packages/app-cli/app/command-sync.ts b/packages/app-cli/app/command-sync.ts
index cb5c42e8fe..4c4d3594b9 100644
--- a/packages/app-cli/app/command-sync.ts
+++ b/packages/app-cli/app/command-sync.ts
@@ -9,11 +9,11 @@ import { appTypeToLockType } from '@joplin/lib/services/synchronizer/LockHandler
 const BaseCommand = require('./base-command').default;
 const { app } = require('./app.js');
 const { OneDriveApiNodeUtils } = require('@joplin/lib/onedrive-api-node-utils.js');
-const { reg } = require('@joplin/lib/registry.js');
+import { reg } from '@joplin/lib/registry';
 const { cliUtils } = require('./cli-utils.js');
 const md5 = require('md5');
-const locker = require('proper-lockfile');
-const fs = require('fs-extra');
+import * as locker from 'proper-lockfile';
+import { pathExists, writeFile } from 'fs-extra';
 
 class Command extends BaseCommand {
 
@@ -37,21 +37,12 @@ class Command extends BaseCommand {
 		];
 	}
 
-	static async lockFile(filePath: string): Promise<Function> {
+	private static async lockFile(filePath: string) {
 		return locker.lock(filePath, { stale: 1000 * 60 * 5 });
 	}
 
-	static isLocked(filePath: string) {
-		return new Promise((resolve, reject) => {
-			locker.check(filePath, (error: any, isLocked: boolean) => {
-				if (error) {
-					reject(error);
-					return;
-				}
-
-				resolve(isLocked);
-			});
-		});
+	private static async isLocked(filePath: string) {
+		return locker.check(filePath);
 	}
 
 	async doAuth() {
@@ -114,7 +105,7 @@ class Command extends BaseCommand {
 
 		// Lock is unique per profile/database
 		const lockFilePath = `${require('os').tmpdir()}/synclock_${md5(escape(Setting.value('profileDir')))}`; // https://github.com/pvorb/node-md5/issues/41
-		if (!(await fs.pathExists(lockFilePath))) await fs.writeFile(lockFilePath, 'synclock');
+		if (!(await pathExists(lockFilePath))) await writeFile(lockFilePath, 'synclock');
 
 		const useLock = args.options.useLock !== 0;
 
diff --git a/packages/app-cli/package.json b/packages/app-cli/package.json
index 7afae85023..4db74d2517 100644
--- a/packages/app-cli/package.json
+++ b/packages/app-cli/package.json
@@ -72,6 +72,7 @@
     "@types/fs-extra": "9.0.13",
     "@types/jest": "29.2.6",
     "@types/node": "18.11.18",
+    "@types/proper-lockfile": "^4.1.2",
     "gulp": "4.0.2",
     "jest": "29.4.3",
     "temp": "0.9.4",
diff --git a/yarn.lock b/yarn.lock
index d91b570fb2..c63467a419 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7727,6 +7727,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/proper-lockfile@npm:^4.1.2":
+  version: 4.1.2
+  resolution: "@types/proper-lockfile@npm:4.1.2"
+  dependencies:
+    "@types/retry": "*"
+  checksum: 9d8a100f96e6df3ce1213eea2696b86de4b75dce3ab5bbc1767226732976bf38d2d2ce1060d6942e76561e8617576547e83bb172e95375192a0b8df1fbca2331
+  languageName: node
+  linkType: hard
+
 "@types/qs@npm:*":
   version: 6.9.7
   resolution: "@types/qs@npm:6.9.7"
@@ -7854,6 +7863,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/retry@npm:*":
+  version: 0.12.2
+  resolution: "@types/retry@npm:0.12.2"
+  checksum: e5675035717b39ce4f42f339657cae9637cf0c0051cf54314a6a2c44d38d91f6544be9ddc0280587789b6afd056be5d99dbe3e9f4df68c286c36321579b1bf4a
+  languageName: node
+  linkType: hard
+
 "@types/scheduler@npm:*":
   version: 0.16.2
   resolution: "@types/scheduler@npm:0.16.2"
@@ -20213,6 +20229,7 @@ __metadata:
     "@types/fs-extra": 9.0.13
     "@types/jest": 29.2.6
     "@types/node": 18.11.18
+    "@types/proper-lockfile": ^4.1.2
     aws-sdk: 2.1290.0
     chalk: 4.1.2
     compare-version: 0.1.2