How to Sync Files Between Your UGREEN NAS and Computer
File sync keeps the same files current in two places. Edit a document on your laptop, and the updated version appears on your UGREEN NAS the next time the sync client checks in. The point of sync is consistency: whichever device you’re working on, you have the current version of your files.
Three things determine how sync actually behaves, and getting them wrong is where most users get frustrated:
- Direction: Sync can be one-way (changes flow from Computer to UGREEN NAS only) or two-way (changes flow from Computer to UGREEN NAS and from UGREEN NAS to Computer). The wrong direction for your workflow either deletes files you wanted to keep or fails to update files you wanted refreshed.
- Deletions propagate: In two-way sync and mirror-style one-way sync, deleting a file on one side deletes it from the other side at the next sync cycle. The NAS isn’t holding a safety copy.
- Sync is not backup: A backup preserves point-in-time copies that survive deletions, ransomware, and accidental edits. Sync mirrors the current state. If a file gets corrupted or encrypted on your computer and the sync runs, you now have a corrupted or encrypted file in two places.
Sync solves “I want my current files available everywhere.” Backup solves “I want to recover something I lost.” You need both, set up as separate tasks. For files you cannot afford to lose, build a separate backup strategy that preserves recoverable copies instead of only mirroring the current file state.
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How to Sync Your UGREEN NAS with Your Computer
- Open the UGREEN NAS client on your local computer. Go to [Sync & Backup] > [Sync], then click “Create Sync Task.”
- Select the sync destination. Choose “Sync This Computer”, then click “Next” to continue.
- Configure Sync Rules:
- Two-Way Sync — changes flow in both directions. Use this when you actively edit files on both the computer and the NAS and want both sides current. Best for shared working folders.
- Sync Computer to NAS Only — changes flow from the computer to the NAS, but not back. Use this when the computer is the source of truth and the NAS is a mirror. Files deleted on the computer will be deleted from the NAS at the next sync.
- Sync NAS to Computer Only — changes flow from the NAS to the computer, but not back. Use this when the NAS is the source of truth and you want a local copy on the computer for offline access or speed. Files deleted on the NAS will be deleted from the computer.
- Select a sync strategy and choose one of the following options as needed:
- Real-time Sync — the client watches the source folder and syncs changes as they happen. Best for active working folders where you want changes to appear on the other side immediately.
- Manual Sync — files only sync when you click Sync Now. Best for large folders you don’t want syncing on every save, or for situations where you want to control exactly when transfers happen.
After making your selection, click “Next Step” to proceed to the preview stage.
- In the [Preview] screen, you can customize the name of the sync task and review the previously configured settings. If any changes are needed, click “Previous” to modify them. Once everything is confirmed, click “Confirm” to create the sync task.
Managing Sync Tasks After Setup
After the task is created, the Sync interface lists all your sync tasks and connected devices. From here you can:
- Click the ··· button next to a device to create another sync task for the same connection
- Click More on an existing task to edit or delete it
- Click the client icon in your computer’s taskbar to see live transfer status and pause running transfers
UGREEN Tip: the UGREEN NAS client must stay running.Sync tasks only execute while the client is active on your computer. If you close the client (not just minimize it), syncing pauses until you reopen it. For uninterrupted sync, leave the client running in the background — most users configure it to launch automatically at startup.
What Happens When You Delete or Edit Files on Both Sides
Sync is useful because it keeps two locations current, but that also means mistakes can travel fast. Delete, overwrite, rename, or move the wrong file, and sync may carry that change to the other side before you notice.
When You Delete a File
Deletion behavior depends entirely on the sync direction you chose:
Two-way sync. Deleting a file on either side deletes it from the other side at the next sync cycle. There is no safety copy left behind on the NAS.
Computer to NAS only. Deleting on the computer deletes from the NAS. Deleting on the NAS does nothing to the computer — the deleted NAS file will be re-created on the next sync, since the computer still has it.
NAS to computer only. Deleting on the NAS deletes from the computer. Deleting on the computer does nothing to the NAS — the deleted computer file will be re-created on the next sync.
The pattern: deletions flow in the direction of sync. If your direction is two-way, deletions flow both ways.
If a file matters to you, sync alone is not enough protection against accidental deletion. The deletion will propagate before you notice. A scheduled backup running daily catches the file in its previous state before the deletion reaches the backup destination.
When You Edit the Same File on Both Sides
If you edit a file on your computer and the same file on the NAS between sync cycles, the sync client has to decide which version wins. UGREEN NASync resolves this by keeping the most recently modified version and treating the older edit as overwritten. The older version is not preserved.
Three ways to avoid the loss:
- For files two people might edit at the same time, use a real collaborative editing tool (Google Docs, Microsoft 365 with co-authoring, Notion) rather than relying on file sync.
- For files one person edits across multiple devices, finish your edits on one device and let sync complete before opening the file on the other device.
- For files that are critical, keep a backup task running separately so older versions remain recoverable even when a conflict overwrites the live copy.
When You Rename or Move a File
A renamed file is often treated by the sync client as a new file rather than as the same file with a different name. The renamed file gets uploaded to the NAS as if it were new, and the original (old name) is either deleted (in mirror or two-way sync) or left in place as an orphan, depending on the configuration.
When You Edit a File and Delete It Before Sync Runs
If you edit a file and then delete it before the next sync cycle, only the deletion propagates. The intermediate edited version never reaches the NAS. Sync transmits current state, not history — if the current state at sync time is “deleted,” that’s what gets transmitted.
If you needed to recover that edit, only a backup with version history would have it.
When the Sync Client Wasn’t Running
Sync tasks only run while the UGREEN NAS client is active. Changes you make while the client is closed — edits, deletions, renames — are not queued or buffered by the client. When the client launches again, it scans the source folder, detects the differences, and processes them according to the sync direction. The behavior is the same as if you’d made the changes with the client running, just delayed.
The Rule That Covers Every Case
Sync transmits current state, not history. Deletions, conflicts, renames, and unsaved changes all behave according to that rule. Anything you might want to recover later belongs in a backup, not just in sync.
Frequently Asked Questions
Is NAS sync the same as a backup?
No. Sync mirrors the current state of your files across two locations. Backup preserves point-in-time copies you can restore from later. For Mac users, a separate NAS backup for Mac workflow can help protect files beyond what sync alone provides.
What happens if I delete a file from my computer? Will it delete from the NAS?
It depends on the sync direction. In two-way sync and computer-to-NAS sync, yes — deleting on the computer deletes from the NAS at the next sync cycle. In NAS-to-computer sync, no — the deleted file gets re-created on the computer at the next sync, since the NAS still has the original.
Can I sync the same folder to multiple computers?
Yes. Each computer needs the UGREEN NAS client installed and signed in to the same NAS user account. Set up a sync task on each computer pointing at the same NAS folder. With two-way sync configured on each, changes from any computer propagate through the NAS to the others.
The catch: if two people edit the same file at the same time, only the most recently saved edit survives. For collaborative editing, use a real document collaboration tool rather than file sync.
Can I sync over the internet, away from home?
Yes. Your UGREEN NAS supports three remote access methods through UGOS Pro, and any of them work for sync from outside your local network:
- UGREENlink is the easiest option. It’s UGREEN’s built-in remote access service, configured in Control Panel → Device Connection → Remote Access, and it doesn’t require a public IP address or router port forwarding. For most users, this is the right choice.
- DDNS lets you reach your NAS through your own domain name. Requires a public IP address and router configuration, so it’s better suited to users comfortable with networking.
- Tailscale creates a private mesh network between your devices and your NAS, avoiding direct public exposure. It runs as a Docker container, so it’s better suited to users who already understand basic Docker container deployment on UGREEN NAS.
Once remote access is configured through any of these methods, the UGREEN NAS client on your computer connects to the NAS the same way it does on your local network, and sync tasks run normally.
A few practical notes for sync over the internet specifically: transfer speeds are limited by the slower of your home upload bandwidth and your remote download bandwidth, which is usually much slower than local-network sync. Large initial syncs are best completed while the computer is on the local network. After that, daily incremental sync over the internet is fine for typical working folders.
For setup details on each method, see UGREEN’s remote access guide.
How is real-time sync different from scheduled sync?
Real-time sync watches the source folder continuously and syncs changes as they happen. you saving a file, the change is on the other side. Best for active working folders.
Scheduled (or manual) sync runs at fixed intervals or when you trigger it. Changes pile up between runs and get processed in batches. Best for folders with constant churn, slow networks, or situations where you want predictable transfer windows rather than continuous activity.
Will sync slow down my computer?
Lightly, in normal use. The UGREEN NAS client runs as a background process and consumes minimal CPU and memory while watching folders for changes. Active transfers use disk I/O and network bandwidth, which can be noticeable during large initial syncs—especially because many small files can slow NAS transfers more than one large file—but are negligible for daily incremental changes.
Conclusion
Sync keeps your working files current across your computer and UGREEN NAS. Backup keeps recoverable copies of your important data. The two solve different problems and need both, configured as separate tasks.
