Even when the Nextcloud synchronisation client reports files are "Up to date", issues can occasionally prevent actual synchronisation. This can be due to corrupted cache files, local file permission problems, or a desynchronised state between the client and the server.

To troubleshoot and resolve Nextcloud client synchronisation issues, follow these steps:

1. Restart the Nextcloud Client

Often, a simple restart can resolve temporary glitches.

1. Right-click the Nextcloud icon in your system tray (Windows) or menu bar (macOS/Linux).
2. Select Quit Nextcloud or Exit.
3. Re-open the Nextcloud client from your applications menu.

2. Check for File Conflicts or Errors

Review the Nextcloud client's activity log for any specific error messages.

1. Open the Nextcloud client application.
2. Click on Activity or Synchronisation activity to see a list of recent actions and any errors.
3. Address any reported issues, such as file conflicts or permission errors, directly.

3. Pause and Resume Synchronisation

Pausing and resuming synchronisation can sometimes re-trigger the sync process.

1. Open the Nextcloud client.
2. Click on the three dots icon (...) next to the account name or the option to Pause sync.
3. Wait for a few seconds.
4. Resume synchronisation by clicking the same icon or option (Resume sync).

4. Force a Full Resynchronisation (Remove Cache)

If the client claims to be up-to-date but is not, the local cache file might be corrupted or out of sync. Removing this cache will force the client to compare all local files with the server again, creating a new cache.

Important: This process will not delete your actual files, but it will take time, especially for large synchronised folders, as it has to re-scan everything.

Windows

    %APPDATA%\Nextcloud

1. Quit the Nextcloud client. Right-click the Nextcloud icon in the system tray and select Quit Nextcloud.
2. Navigate to the Nextcloud configuration directory. Open File Explorer and paste the above path into the address bar:
3. Locate and delete the sync-journal.db file. This file stores the client's synchronisation state.
4. Restart the Nextcloud client from your applications menu. The client will now re-scan all local and remote files.

macOS

    ~/Library/Application Support/Nextcloud

1. Quit the Nextcloud client. Click the Nextcloud icon in the menu bar and select Quit Nextcloud.
2. Open Finder.
3. In the menu bar, click Go -> Go to Folder... (or press Shift + Command + G).
4. Paste the above path:
5. Locate and delete the sync-journal.db file.
6. Restart the Nextcloud client from your Applications folder.

Linux

    killall nextcloud || nextcloud --quit # Ensure the client is fully closed
    rm ~/.config/Nextcloud/sync-journal.db

1. Quit the Nextcloud client.
2. Open a terminal.
3. Navigate to the Nextcloud configuration directory and delete the sync-journal.db file:

Note: The path ~/.config/Nextcloud/ is common, but it might vary for some distributions or custom installations. If you can't find it there, check ~/.local/share/Nextcloud/ or other system-specific configuration directories.

1. Restart the Nextcloud client.

5. Re-add Account (If troubleshooting steps above fail)

If problems persist, completely removing and re-adding your Nextcloud account from the client can often resolve deeply rooted synchronisation issues.

Important: This will temporarily remove the connection but will not delete your files on the server or in your local synchronised folder. However, the client will need to re-establish the connection and potentially re-index all files.

1. Open the Nextcloud client.
2. Go to Settings -> Account.
3. Select the problematic account and click Remove account. Confirm when prompted.
4. Click Add account and follow the prompts to reconnect to your Nextcloud server. You will need your server address, username, and password.

6. Check Server-Side Issues (Advanced)