Synology NAS: deleted files but space won't go down

Have you ever experienced a situation where you delete files from your Synology NAS (Network Attached Storage) device, but the available space doesn't seem to decrease? This can be a puzzling issue, but don't worry, we're here to help you understand why this happens and how to resolve it.

Before we delve into the details, let's first understand how data is stored on a Synology NAS. When you delete a file from your NAS, it is moved to the "Recycle Bin," which acts as a temporary storage for deleted files. The files remain in the Recycle Bin until you manually empty it or until it reaches its maximum capacity, at which point the oldest files are automatically deleted to make room for new ones.

Now, let's explore some possible reasons why the available space on your Synology NAS might not go down even after deleting files:

1. Recycle Bin not emptied

The most common reason is that the Recycle Bin has not been emptied. When you delete files, they are moved to the Recycle Bin, and until you empty it, the files will still occupy space on your NAS. To empty the Recycle Bin, follow these steps:

1. Open the Synology DSM (DiskStation Manager) web interface.
2. Navigate to "Control Panel" and click on "Shared Folder."
3. Select the shared folder with the Recycle Bin you want to empty.
4. Click on the "Action" button and choose "Empty Recycle Bin."
5. Confirm the action when prompted.

After emptying the Recycle Bin, the space on your NAS should reflect the deleted files.

2. Snapshot retention

If you have enabled the Snapshot feature on your Synology NAS, it could be the reason why the available space doesn't decrease. Snapshots are point-in-time copies of your data that allow you to restore previous versions of files or folders. By default, Synology NAS retains a certain number of snapshots, which can consume a significant amount of storage space.

To check and manage the snapshot retention settings, follow these steps:

1. Open the Synology DSM web interface.
2. Navigate to "Control Panel" and click on "Shared Folder."
3. Select the shared folder with snapshots enabled.
4. Click on the "Action" button and choose "Snapshot Replication."
5. Adjust the snapshot retention settings according to your requirements.
6. Click "Apply" to save the changes.

Reducing the number of snapshots or increasing the interval between snapshots can free up space on your NAS.

3. File indexing and thumbnail generation

Synology NAS has a feature called "File Indexing" that creates an index of the files stored on your device. Additionally, if you have enabled thumbnail generation, it creates small preview images for various file types. These processes can take up storage space, especially if you have a large number of files or if the files are large in size.

To check and manage the file indexing and thumbnail generation settings, follow these steps:

1. Open the Synology DSM web interface.
2. Navigate to "Control Panel" and click on "Indexing Service."
3. Disable indexing and thumbnail generation for specific folders or file types if necessary.
4. Click "Apply" to save the changes.

Disabling file indexing and thumbnail generation can help free up storage space on your Synology NAS.

4. File system corruption

In rare cases, file system corruption can cause the available space on your Synology NAS to not decrease after deleting files. This can happen due to various reasons, such as improper shutdowns or hardware issues. If you suspect file system corruption, it is recommended to run a file system check on your NAS.

To run a file system check on your Synology NAS, follow these steps:

1. Open the Synology DSM web interface.
2. Navigate to "Storage Manager" and click on "Volume."
3. Select the volume you want to check.
4. Click on the "Action" button and choose "Check File System."
5. Follow the on-screen instructions to start the file system check.

Running a file system check can help identify and resolve any issues that might be causing the incorrect reporting of available space on your Synology NAS.

We hope this article has provided you with a better understanding of why the available space on your Synology NAS might not go down even after deleting files. By following the steps outlined above, you should be able to resolve the issue and ensure accurate space utilization on your NAS.

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