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The error: Synology Cloud Sync not syncing all files

Synology Cloud Sync is an application provided by Synology to help users sync files between their Synology NAS and public cloud services. Marriage sigil. It supports various cloud services, including Amazon Drive, Dropbox, Google Cloud Storage, Microsoft Azure, and more. You are allowed to perform one-way or two-way sync between your NAS and other cloud services. You can also schedule the specific time and date to run automatic sync.

Synology Cloud Station as DIY Dropbox Alternative Cloud Station. The Cloud Station service runs on the Synology as a free user installed application. It's configured with. Cloud Sync for Mac. The NAS to NAS syncing is nice but it's the Mac syncing client that starts to show off the real. Step 1: Copy and paste the folder you want to sync with the Dropbox folder. Move the folders you want to sync with the Dropbox folder. Step 2: Create a symbolic link. Right-click on the folders you want to access from another location, move the cursor over the 'Send To' option, and click on 'Desktop'. Click the Dropbox icon from the taskbar (Windows) or menu bar (Mac). Click your avatar (profile picture or initials). Select Preferences. Click Selective Sync (Windows and Linux) or Choose folders to sync (Mac). Uncheck the boxes of any folders that you don't need on your computer's hard drive.

I have a Synology NAS and looking into several options to sync it to the cloud. I started a trial for Dropbox Business and testing it out with some folders. I have a 7TB archive of RAW-files, each between 24-30MB/file. And did a test with 1,5GB fodler. Average upload speed from NAS to Dropbox using Cloud SYnc was 3,5MB/s.

Powerful as Synology Cloud Sync seems to be, it fails to work sometimes. Some users find Synology Cloud Sync not syncing all files, only saying 'Up to date'. After trying to reinstall Cloud Sync and change DNS, there’s no difference. How frustrating it is!

Why and how to resolve Synology Cloud Sync stops syncing?

The Synology Cloud Sync not working problem can be caused by improper connection on Cloud Sync, low version of Cloud Sync, and the limitations imposed by cloud service providers. You can fix the issue with the following solutions:

Solution 1: Reconnect Synology NAS and the cloud

1. On the Cloud Sync user interface, select the connection which has an issue from the left panel.

2. Under the Overview tab, click Manage. Then, choose Unlink to remove the connection of your Synology NAS and the cloud.

3. Click on the “+” icon at the bottom-left corner to create the connection again. Cloud Sync should then start syncing the remaining folders and files.

Solution 2: Auto update Cloud Sync

Sometimes, the Synology Cloud Sync not syncing issue can result from low version of Cloud Sync. To fix it, please go to Package Center, click on the Cloud Sync package, and choose Auto-update from the drop-down menu.

Solution 3: Check limitations of a specific cloud

When you encounter the error of Synology Cloud Sync not syncing all files, you can also fix it by checking out the limitations of a specific cloud. Take Dropbox as an example. Files will not be synced by Cloud Sync if: (Learn more about cloud limitations >>)

  • The file name starts with .dropbox or .cache.

  • Thefile/folder name is/contains .dropbox.

  • The file has been uploaded for more than 48 hours.

To fix the problem of Synology Cloud Sync Dropbox not working, you can filter out certain file names in the following steps:

1. Select the cloud service that has an error from the connection list on the left.

2. Go to the Task list tab, select a sync task and click Edit.

3. Select the folders you want to sync under the Folder tab and prevent certain files from being synced under the File Filter tab.

4. Click Apply to save your settings.

Easier way to sync files between Synology NAS and a cloud drive

If you have tried all the above solutions but still find Synology Cloud Sync not syncing all files, it is time to resort to another file sync tool. AOMEI Backupper Standard, the best free file sync software for Windows 10/8.1/8/7/Vista/XP, comes to help.

  • Various sync sources and destinations: AOMEI Backupper Standard allows you to sync files between two folders, drives, or even two computers. You can also sync NAS to cloud, such as sync QNAP to OneDrive.

  • Schedule settings: You are allowed to create a daily/weekly/monthly sync task. It will automatically install a service to run missed sync at the next system startup.

  • Sync settings: You can set email notification to inform you of sync results and choose to sync deletions or not, etc.

Follow the guidance below to sync files between Synology NAS and a cloud drive:

Step 1. Download, install and run this free file sync tool.

Step 2. Click Sync and select Basic Sync. Basic Sync will perform one-way sync between Synology NAS and the cloud. If you want to perform two-way sync, please upgrade to AOMEI Backupper Professional.

Step 3. Edit the task name based on your needs. Then, click Add Folder >Share/NAS >Add Network Location to add the Synology NAS path.

Step 4. In the Add Network Location window, type the IP address of Synology NAS and click OK. Type username and password if it is needed.

Step 5. After Synology NAS has been added, all the folders under it will be listed. Choose the folder you want to sync and click OK.

Step 6. Click the right edge of the second bar and choose Select a cloud drive.

Step 7. Select a cloud from the list and click OK. If you don’t see your desired cloud in the list, then go back to Step 6 and manually navigate to the cloud local folder by clicking the second bar.

Step 8. Confirm the source and destination directory and click Start Sync.


To resolve Synology Cloud Sync not syncing all files, you can try the solutions offered in this article. If you are disappointed at Synology Cloud Sync, you can turn to AOMEI Backupper. The sync process with AOMEI Backupper is easier, and it supports not only Synology NAS but also QNAP, WD My Cloud, and Seagate Personal Cloud, etc.

What’s more, AOMEI Backupper is powerful hard drive transfer software that can help you transfer OS and data from one hard drive to another. Why not try it now?

Learning has never been so easy!

This is a How-To on using CloudSync on a Synology NAS based on my experience with the product.
Cloud Sync is a feature that allows you to connect and sync content you have in your cloud accounts to your Synology NAS for that extra piece of mind. There are many cloud providers that are supported such as:
• Dropbox
• Google Drive
• Micosoft OneDrive
• Amazon Drive
• Baidu Cloud
• Box
• Azure Cloud
• Backblaze 2
These are just a few and I don’t have experience with all of them, so will only be showing how to connect to Dropbox, which should be a similar process across all of them.

14 Steps total

Step 1: Open Cloud Sync

Install Cloud Sync from the package centre if not already installed and open the application.

Step 2: Choose a cloud provider

2. Click on the cross in the lower left hand corner which will open this page

Step 3: Choose Dropbox (Or any other provider you want)

In this How-To, I will be connecting to Dropbox, so choose Dropbox and click the next button.

Synology Dropbox Sync App

Step 4: Choose Online account to connect to

Next to appear (for the Dropbox account, and this is the same as Box and Google Drive) is the API window looking to connect your application to your cloud service.

Step 5: Agree to sync

Synology Dropbox Sync Software

Once you have logged into your cloud account, press the “Agree” button to allow syncing.

Step 6: Choose a folder to sync to

Next you will need to click on the file in “Local Path” to create a folder to sync the data to or choose an existing folder.

Step 7: Choose how you want it to sync

The root folder chosen for “Remote Path” is meaning to sync all folder structures of your online account. You can choose how you want to sync, bidirectional will mean any changes made to this folder on the Synology will sync to the online account. You can change this to just sync to the Synology one way if you like.

Step 8: The encryption option

There is an encryption option, please see screenshot for explanation.

Synology And Dropbox Sync

Step 9: Scheduling of sync

Next choose the Schedule settings, if you would like to control when you would like it to sync, i.e. outside of production times or not in peak Netflix viewing times. This is especially handy for households with limited internet speeds. Leave un-ticked if happy to sync in real time.

Step 10: Advanced Folder sync settings

Synology Dropbox Sync Tool

To see advanced settings where you can choose which folders you would like to sync from the cloud account, press the Advanced button.

Step 11: File filter in Advanced Settings

You can also choose to sync certain types of files and not others.

Step 12: Confirm Settings

Check and confirm your settings and then press Apply.

Step 13: Console

The console gives a great overview of the sync status, the task list and schedule settings.

Step 14: File History

You can also check the file history of the sync which is also a handy feature.

I use this on my personal Synology DS214Play and find it handy to have an offline copy of my online cloud accounts.
Hopefully you will find this How-To handy. :)


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