By Ivy / Last update July 15, 2022

The Issue: Synology Cloud Sync Not Working

Synology Cloud Sync is a feature of Synology NAS, which allows you to sync data between local Synology NAS and cloud drives, these clouds include Google Drive, Dropbox, OneDrive, Amazon Drive, etc. It is capable of doing one-way sync and two way sync (bidirectional sync), schedule sync. However, some users report the Synology Sync not working, just like the following case:

“I had Cloud Sync running fine several months, to sync one of my folders on Synology NAS to My Dropbox. A couple of days ago, Synology Cloud Sync stopped syncing, and showing ‘Connecting’, so i restart the task, still the same problem, I can’t find a solution to fix it, what should i do to sync data? Please help, Thanks.”

Synology Cloud Sync Connecting

In fact, it's not the only situation for Synology Cloud Sync not working problem. Sometimes, it says up to date (actually it’s not) and did not sync anything. Even without a usage prompt, simply displays an unknown error. Thus, the reasons may be various, such as, lower version, poor network connection, not enough space, incorrect configuration, etc.

Quick Fixes to Synology Cloud Sync Not Working

After understanding this error and the causes, try the following solutions. It's saide to be proven, but not 100% guaranteed. Please be sure you are using the latest Synology Cloud Sync and Dropbox. If it is, but still not working, continue using other solutions.

Wat 1: Check Your Internet Connection 

If the Synology Cloud Sync start syncing files for a while and then stop working, this may be caused by poor network connect. Please be sure there is a good connection while syncing files to Cloud Drive.

Way 2: Upgrade Dropbox for More Space

The Synology Cloud Sync stuck issue may als be caused by not enough cloud space, in this case, you need to check cloud storage for Dropbox. If it is full, try the following operations or directly upgrade Dropbox:

  • Complete the getting started checklist.
  • Invite your friends - up to 16 GB.
  • Submit feedback to Dropbox.
  • Try Dropbox Business free for 30 days.

Way 3: Unlink and Relink Dropbox Account

If the Synology Cloud Sync and Dropbox not connect well, you may receive the Synology Cloud Sync Dropbox not working issue. For this situation, click Unlink under the Manage option. 

Remove Connection

Then, click + at the lower left corner to add Dropbox. In the Cloud Providers page, select Dropbox and press Next. Click Allow > Agree when you are asked to grant access priority for Synology. 

Relink Dropbox

Next, specific source and destination folder respectively in Synology NAS and Dropbox. Select the sync direction, either one-way or two sync, press Next and click Apply to relink the Dropbox account.

Relink Successfully

Way 4: Resume Synology NAS and Sync Your Files

If it says up to date, but the Synology Cloud Sync stuck as well. Click the Manage button under it and select Pause Syncing

Pause Syncing

Then, wait for a few minutes, select Resume Syncing under Manage. This time you may be able to run Synology Cloud Sync normally. 

Resume Syncing

Way 5: Get cloud authority again

Sometimes, the Synology Cloud Sync not working due to the expired authorization of the cloud API. Because Synology Cloud Sync does not prompt you about this problem just fails silently. 

However, you might get the “Unknown error occurs. Please try again later.” message after reconnecting your Clouds.

Synology Cloud Sync Unknown Error Occurs

Besides, Cloud Sync does not allow you to sync incremental parts, even only a few changes on your file, you have to download or upload the file.

Workaround to Sync Synology NAS to Dropbox

You may have already fixed Synology Cloud Sync not working issue with the above solutions. But you need to run it manually every time. To avoid this situation, you can choose to schedule stop and start sync task in Synology Cloud Sync or use third-party software for help. 

Set a scheduled task to stop and start Synology Cloud Sync 

The Synology Cloud Sync provides users with service action, either stop or start service, thus you can easily restart the Synology Cloud Sync. Please follow the steps below:

Step 1. Open Synology Cloud Sync, go to Control Panel > Task Scheduler. Then, click Create > Scheduled Task > Service.

Create Scheduled Services

Step 2. In the Edit Task window, set general settings, schedule and task settings, click Next. 

  • For General Settings, you can specify the task name, CloudSync Stop, for example, and then select user.
  • For Schedule, you are able to specify the schedule date and time. My stop time is 10 pm every night.
  • For Task Settings, you are capable of selecting service action, here is Stop service, and then Cloud Sync app under Packages. 

Stop Synology Cloud Sync

Step 3. follow the steps above but this time you need to select Start services in the Task Settings tab. The start time needs to be later than the stop time. my start time is 5 minutes after stop time. You can select a shorter or longer time. 

Start Synology Cloud Sync Schedule

Run Synology Cloud Sync Schedule With Third-Party Software

As the best file sync software - AOMEI Backupper Professional allows you to sync Synology NAS to clouds easily in Windows XP, Vista, 7, 8, 8.1, 10, 11. It’s highly recommended by millions of users due to its reliable performance, comprehensive features and intuitive interface.

There are multiple sync features provided in this file sync software:
👍 Basic Sync: Sync files and folders to local disk, external hard disk, USB flash drive, CD/DVD, network share or NAS, cloud drives, schedule sync, etc.
👍 Mirror Sync: Always keep the files in the destination exactly the same as the source.
👍 Real-Time Sync: Once the changes made on the source, it will sync changed or newly added files and folders to the destination immediately.
👍Two-Way Sync: Sync files and folders from each other. Any changes in the source or destination directory will be synced to the other side.

And you can set the sync task to run schedule, such as, daily, weekly, monthly, event trigger and USB plug in. Among them, the daily sync is limited to only once or ranges from every 1 hour to 6 hours. Thus, you can automatically sync files in simple steps.

Please download it to have a try! For server users, try AOMEI Backupper Server.

Download Free TrialWin 11/10/8.1/8/7/XP
Secure Download

Step 1. Perform AOMEI Backupper Professional, and choose Real-Time Sync at the Sync tab.

Real Time Sync

Step 2. Click + Add Folder button > Share/NAS > Add Share or NAS Devices > input the Network Path (IP address of Synology NAS), user name and password, and click OK to add Synology NAS, and choose the folders you prefer to sync.

Add Folder

add share or NAS device

★Tip: Rename Task Name for the real time sync task if you want to differ from other sync tasks.

Step 3. Tap the inverted triangle icon > Select a cloud drive > choose Dropbox as the destination.

Select a Cloud Drive

Select Dropbox

★Tip: Ensure you have installed Dropbox desktop app first.

Step 4. Click Start Sync >> to sync Synology NAS to Dropbox automatically in Windows 10.

Start Sync Synology NAS To Dropbox

★Tips:
The Options could allow you to comment on the sync task, check the integrity of files in the destination during synchronization, etc.
To sync files with a longer frequency, try Basic Sync, Mirror Sync or Two-Way Sync. 

After the first full file sync is finished, any changes on the source directory will be immediately synced to the destination since the last file sync (sync in real time) to save your Dropbox cloud storage space.

Write in the End

Find the solutions to fix Cloud Sync in Synology NAS not working, If you can’t solve it, please try workarounds to schedule sync files in Synology NAS.  To schedule sync task more flexible, even in real-time, try file sync software - AOMEI Backupper Professional. It not only helps you sync files from one location to another, but also between two location. Thus, you don't need to worry about missing any change.