Synology Drive not syncing files: causes and solutions

In this post, we'll tell you the most common reasons why Synology Drive isn't syncing files. They range from names with prohibited characters or specific rules that prevent synchronizationThe good news is that, in most cases, you won't need to contact technical support.

Synology Drive not syncing files: causes and solutions

Synology Drive Client can be an extremely reliable tool for synchronizing files between computers, NAS devices, and other equipment. But it can fail. When Synchronization stopsThe workflow breaks down, and a frantic search for causes and solutions begins. Why isn't Synology Drive syncing files?

It's worth clarifying that Synology Drive synchronization problems rarely stem from a serious failure. Almost always, the cause lies in one of these three areas: blocking rules, disallowed file attributes, or permission conflictsThe idea is to make a quick diagnosis that allows us to rule out the cause layer by layer. Let's begin.

Quick diagnosis: Read the records and have the client tell you the cause.

If Synology Drive is not syncing files, the first thing to do is Go to the Logs section to view "Not Synchronized" eventsThere you'll find out exactly which files have been omitted and why. Common warnings include exclusions based on synchronization rules, paths exceeding the allowed limit, filenames with special characters, permission errors, files in use, etc.

The clues provided by the logs are usually much faster than a manual investigation. The best part is that you immediately know why Synology isn't syncing files and which ones have failed. And with that, you can... Apply one of the listed solutions Next. These steps are also useful if the logs show no errors, but the file still won't sync.

Next step: synchronization rules and folder selection

This is the most overlooked cause and, at the same time, the easiest to resolve. The first thing to check is if the selective synchronization And secondly, if there is active filters To exclude by size or extension type. If you forgot you configured it or ignore it, you won't be able to solve the problem until you modify it.

For selective synchronization, open Synology Drive Client and go to Synchronization task – Select task – Synchronization rules and look at the tab "File". Folders that are not checked will not be synced: select the ones you need to back up and you're done.

On the same page, «File filter» You may have set a size limit or exclude certain extensions, such as .tmp or .iso. If you sync large videos or design materials, check if you have enabled the default size limit. Let's now look at other reasons why Synology might not be syncing files and what to do to fix it.

Synology Drive does not sync files: file names, paths, and attributes

When Synology Drive fails to sync files, pay close attention to the following: file names, paths, and attributes that we want to back up. This is especially true in multiplatform environments where several file systems are used. In these cases, incompatibilities are unavoidable, but they can be avoided by applying simple adjustments.

Let's start with the number one culprit: special charactersIn Windows environments, files whose path contains * : ? \ / " < > | Names beginning with an accent mark are omitted. ~ They're not valid. macOS and Linux, on the other hand, are more permissive, but the slash / It remains prohibited.

Therefore, inconsistencies can arise when attempting to synchronize files from Windows, macOS, and Linux simultaneously. A filename that is legal in Linux but contains a colon will be considered invalid by the Windows client. Similarly, files are rejected in Windows if their paths contain a colon. file or folder path exceeds 247 characters.

Likewise, there are some Windows file attributes that also blockFor example, the attributes SYSTEM, TEMPORARY, OFFLINE o REPARSE_POINT These attributes are automatically ignored by Synology. Some temporary files generated by installers and system backups often carry these attributes. The solution? Right-click on the file – Properties – Details, check, and rename if necessary.

Insufficient permissions or file in use

"The file is in use or access is denied" is another very common error. The reason is straightforward: Word has the document open, Photoshop has locked the file, or your user account doesn't have full read and write permissions. The solution? Close the file and the application that is using it..

If the error persists in Windows, check the Task Manager that there is not background processes blocking the elementYou can also try it on Windows. LockHunterThis will tell you exactly which process is using the target file. On a Mac, you should check the "Full Disk Access" permission in System Settings – Privacy & Security, and confirm that Synology Drive Client is authorized.

Another reason why Synology Drive isn't syncing files is the editing conflict between protocolsLet's say you're syncing a file using the client and simultaneously accessing the same file through a mapped SMB drive. In these cases, file locking mechanisms in some applications (especially databases and office suites) can cause the sync to fail. To avoid this, try unifying your access methods: either use Drive or SMB.

Nothing works: Synology Drive won't sync files

Is Synology Drive still not syncing files? Maybe You have exceeded the maximum space quota allocated to your user.In this case, start by freeing up space on the NAS, emptying the Synology Drive Admin Console recycle bin, or increasing the user quota from the Control Panel.

But if the entire diagnosis fails, you have to contact Synology technical supportThey will ask you for the system logs and the customer diagnostic logs, which you can get from Troubleshooting – Export diagnostic logs.

However, before requesting support, try the recommendations in this article. Check the logs, verify the synchronization settings, and ensure that the names, paths, and attributes are correct. Also, verify that you have sufficient permissions and that the file in question is not in use. With this, you should be able to resolve the issue. You can solve the problem in less than ten minutes.