By the end of this guide you will have a dedicated shared folder on your NAS for backups, automated versioned protection for one or more PCs and Macs, retention rules that prevent your drive from filling up, and a tested restore process you can rely on. You will create separate folders for each device and backup type, set permissions so only the right users can access them, and schedule backups to run without manual intervention.
Prerequisites: Your NAS is powered on, connected to your router via Ethernet, initialized with at least one storage pool and volume, and reachable from your computer on the same local network. You should know your NAS admin username and password, have about 30 to 45 minutes, and have at least 1.5x the size of the data you plan to back up in free space on the NAS.
Before You Start
Getting these items ready first prevents permission errors and failed first backups. The table below covers what is essential and what is nice to have.
| What you need | Why | Optional? |
|---|---|---|
| NAS admin account and DSM / QTS / ADM password | Required to create shared folders, users, and backup services | No |
| NAS with healthy Storage Pool and Volume (e.g., Synology DSM: Storage Manager > Storage > Storage Pool / Volume) | Backup folders cannot be created without a formatted volume using Btrfs or ext4 | No |
| Computer on same LAN with SMB access | To map the drive and test restore; Windows needs File Explorer, Mac needs Finder > Go > Connect to Server | No |
| Dedicated backup user account (e.g., backup_svc) | Isolates backup permissions from your daily account and prevents accidental deletion | Recommended |
| UPS or surge protection for NAS | Prevents corruption of backup database during power loss | Yes |
| External USB drive for secondary copy | Allows Hyper Backup or USB Copy to keep an off-site copy per 3-2-1 rule | Yes |
Step-by-Step
Step 1: Create a Dedicated Shared Folder for Backups (Time: 3 minutes)
Log in to your NAS web interface. On Synology DSM 7.2, go to Control Panel > Shared Folder > Create > Create Shared Folder. On QNAP QTS 5.1, go to Control Panel > Privilege > Shared Folders > Create > Shared Folder. Name it clearly, for example backup_pcs or backup_mac_timemachine. Avoid spaces; use underscores. Set Location to Volume 1, enable Recycle Bin if your file system is Btrfs, and check Enable data checksum for advanced data integrity. Click Next, enable Encrypt this shared folder only if you need at-rest encryption and you have stored the key in a password manager, then click Apply. Do not store personal documents directly in this folder; it should only contain backup databases.
Step 2: Create Subfolders and a Service Account with Correct Permissions (Time: 4 minutes)
Create one subfolder per device inside the share via File Station > backup_pcs > Create > Create Folder. Example structure: /backup_pcs/desktop-win11, /backup_pcs/laptop-win11, /backup_mac_timemachine/macbook-pro. Keeping devices separate prevents version conflicts and makes retention easier to manage.
Next, create a limited user. Go to Control Panel > User & Group > User > Create. Username: backup_svc, password: 16+ characters. Assign to no admin groups. On the Shared Folder permission screen, give this user Read/Write to backup_pcs and No Access to all other shares. Under Applications, deny access to everything except SMB and the backup app you will use (e.g., Active Backup for Business or Hyper Backup). Apply and note the credentials. Key combo to quickly open Windows credential manager to store this account is Win + R, then type control keymgr.dll and press Enter.
Step 3: Enable and Harden the File Service You Will Use (Time: 3 minutes)
For Windows File History or Active Backup, you need SMB. Go to Control Panel > File Services > SMB > Enable SMB Service. Set Minimum SMB protocol to SMB2 and Maximum to SMB3, enable Transport encryption if all clients support Windows 10/11 or macOS 13+. For Mac Time Machine, also enable AFP only if you have a legacy Mac; otherwise use SMB. Go to Control Panel > File Services > Advanced > Bonjour > Enable Time Machine broadcast and select your Time Machine share.
Set file locations for logs: Control Panel > File Services > SMB > Advanced > Log Level: Transfer log. This helps you audit later at Log Center > Logs > File Transfer.
Step 4: Set Quotas and Retention to Prevent Drive Full Errors (Time: 4 minutes)
Without quotas, one PC can consume the entire NAS. Go to Control Panel > User & Group > User > Edit backup_svc > Quota. Enable quota and set a value range of 500 GB to 2000 GB per device, depending on your volume size. For example, if you have a 4 TB volume and two PCs, set 1500 GB per device, leaving 1 TB headroom for snapshots and system use.
If using Synology Active Backup for Business, go to Active Backup for Business > Active Backup for Business Agent > Settings > Retention Policy. Choose Customized retention: keep all versions for 7 days, keep one version per day for 30 days, one version per week for 52 weeks. If using Synology Drive or File History to a shared folder, enable snapshots: Control Panel > Shared Folder > Select backup_pcs > Snapshots > Snapshot > Settings. Schedule snapshot every day at 02:00 and retain 30 snapshots. This gives you versioning at the filesystem level even if the client software fails.
Step 5: Connect Windows with File History or Active Backup (Time: 8 minutes)
Option A – File History (simple file-level backup): On Windows 11, go to Settings > System > Storage > Advanced storage settings > Backup options > Add a drive. Click Show all network locations and enter \\YOUR-NAS-IP\backup_pcs\desktop-win11. When prompted, enter backup_svc credentials and check Remember my credentials. Click Turn on. Click More options to set Back up my files every 1 hour, Keep my backups for Until space is needed or 3 months, and Add folders such as C:\Users\YourName\Documents.
Option B – Full system image with Active Backup for Business (recommended as of 2026 for bare-metal restore): On the NAS, install Active Backup for Business from Package Center > Search Active Backup for Business > Install > Open. On the Windows PC, download the agent from the NAS page at http://YOUR-NAS-IP:5000 > Connect to > Active Backup for Business Agent for Windows. Install, enter NAS IP, username backup_svc, and select Backup Task > Create > PC > Entire device or Custom volume (C:). Set Schedule to Daily at 19:00 when PC is likely on, enable Backup encryption with a separate password stored offline, and set Compression to Client-side. Click Backup Now for the first run, which will take longer than incremental runs.
Step 6: Connect macOS with Time Machine to a Dedicated Share (Time: 6 minutes)
On the NAS, create a Time Machine-specific share if you have not already: Control Panel > Shared Folder > Create > Create Shared Folder > Name: backup_mac_timemachine. Go to Control Panel > File Services > SMB > Advanced > Enable Bonjour Time Machine broadcast via SMB > Set Time Machine Folders > Select backup_mac_timemachine. Set a quota range of 2x to 3x your Mac internal drive; for a 512 GB Mac, set 1000 GB to 1500 GB in Control Panel > Shared Folder > Select backup_mac_timemachine > Edit > Advanced > Enable shared folder quota.
On the Mac, go to System Settings > General > Time Machine > Add Backup Disk. Select your NAS from the list (it appears as YOUR-NAS.local). Choose Use Disk, check Encrypt backups, and enter the backup_svc credentials. macOS will mount at smb://YOUR-NAS-IP/backup_mac_timemachine and create a sparsebundle named MacBook-Pro.sparsebundle inside that share. To force the first backup immediately, click Options > Back Up Now from the Time Machine menu bar icon (enable it via Control Center > Time Machine > Show in Menu Bar).
Verify It Worked
Do not assume the green checkmark means data is restorable. Run these checks within 10 minutes of the first backup completing.
On the NAS, open File Station > backup_pcs > desktop-win11. Confirm files exist and show a recent Modified timestamp within the last hour. For Active Backup for Business, go to Active Backup for Business > Overview > Task List and verify Last backup result: Success and that Version count increments after the second scheduled run.
On Windows, test a file restore: Right-click any file in Documents > Properties > Previous Versions, or open Settings > System > Storage > Advanced storage settings > Backup options > Restore files from a current backup. Restore a single test file to C:\Temp\RestoreTest and open it.
On Mac, enter Time Machine > Browse Time Machine Backups and restore a test document to Desktop. Then verify NAS-side protection: Control Panel > Shared Folder > Snapshots > Snapshot List should show a new snapshot created at the scheduled time with Status: Healthy. Check Log Center > Logs > File Transfer for SMB login entries from backup_svc at the expected backup hour.
Mistakes to Avoid
1. Giving Everyone Read/Write to the Backup Share
What causes it: Leaving the default permission Everyone: Read/Write or granting your daily user admin rights to the backup folder for convenience.
How to check: Go to Control Panel > Shared Folder > Select backup_pcs > Edit > Permissions. If any user or group besides backup_svc and admins shows Read/Write, it is too open. Also check File Station > Right-click folder > Properties > Permission.
What to do: Set backup_svc to Read/Write, administrators to Read/Write or Read Only, and all other users and groups to No Access or Custom: Deny. Disable guest access under Control Panel > File Services > SMB > Advanced > Others > Deny guest access.
How to undo: Return to the same Permissions tab and restore Read/Write to the affected user if a legitimate app loses access. Apply and re-authenticate on the client with Win + R > cmdkey /delete:YOUR-NAS-IP then reconnect.
2. Backing Up to the Same Volume Without Versioning or Quotas
What causes it: Pointing backups at a general share like home or public without snapshots, retention, or quotas, so a ransomware event encrypts both live data and backups and a single device fills the volume.
How to check: In Storage Manager > Volume, note if backup_pcs lives on the same volume as active data and check Control Panel > Shared Folder > Snapshots to see if snapshots are Disabled and Quota shows Unlimited.
What to do: Move backups to a dedicated share as in Step 1, enable Btrfs snapshots daily retention 30 days, and set a per-user quota between 500 GB and 2000 GB. In Active Backup for Business, enable retention policy with at least 7 daily versions.
How to undo: Disable snapshots or set quota back to Unlimited on the Quota tab if you need temporary space for a large one-time backup, then re-enable after it completes.
3. Using SMB1 or Weak NTLM Settings
What causes it: Enabling SMB1 for compatibility with old devices or setting Control Panel > File Services > SMB > Advanced > NTLMv1 enabled, which reduces security and can cause Windows 11 to block connections.
How to check: On the NAS, verify Minimum SMB protocol is SMB1. On Windows, run PowerShell > Get-SmbConnection and check Dialect is 2.x or 3.x; if it shows 1.5 or fails to connect, the NAS is misconfigured.
What to do: Set Minimum SMB protocol to SMB2, Maximum to SMB3, disable NTLMv1, and enable SMB encryption if supported. On Windows, enforce via Settings > Apps > Optional Features > turn off SMB 1.0/CIFS File Sharing Support.
How to undo: Temporarily re-enable SMB1 under File Services > SMB > Advanced if a legacy device cannot connect, then isolate that device to a separate VLAN or share and disable SMB1 again.
4. Never Testing Restore Until Disaster
What causes it: Assuming scheduled tasks succeeded because no error notification appeared, while backup database is corrupted or credentials expired.
How to check: Look for gaps in Active Backup for Business > Reports > Backup Calendar or Time Machine > Backups where dates are missing. Check Log Center > Logs > System for authentication failures for backup_svc.
What to do: Schedule a monthly restore test to C:\Temp\RestoreTest or ~/Desktop/RestoreTest and verify file integrity. Enable notifications: Control Panel > Notification > Email or Push Service > enable alerts for backup failure and storage quota exceed.
How to undo: Delete the test restore folder after verification. If notifications are too noisy, change Notification > Rules to only send on Error, not on Success.
FAQ
Should I use one backup folder for every device or separate folders?
Use separate subfolders per device and per backup type, all inside one parent share with a quota. For example, /backup_pcs/desktop-win11 for File History and /backup_mac_timemachine/macbook-pro for Time Machine. This prevents file name collisions, lets you set per-device quotas between 500 GB and 1500 GB, and makes it simple to wipe one device backup without affecting others. Set permissions at the parent share level and inherit to subfolders via File Station > Right-click > Properties > Permission > Apply to sub-folders.
How much space should I allocate for NAS backup folders?
Allocate 1.5x to 2x the used space on the source device for file-level backups, and 2x to 3x for versioned image backups or Time Machine. A 1 TB used Windows drive needs 1500 GB to 2000 GB quota for 30 days of hourly File History versions. Check actual usage via File Station > Right-click backup_pcs > Properties > Usage, and Storage Manager > Volume > Used / Available. If the NAS volume exceeds 80 percent used, increase the volume, prune retention from 30 to 14 days, or move older versions to an external USB share via Hyper Backup > Create > Data backup task > Local folder & USB.
Can I back up over Wi-Fi or do I need Ethernet?
Initial backups should be over Gigabit Ethernet to avoid timeouts; a 500 GB first backup can take 4 to 8 hours on Gigabit and much longer on Wi-Fi. Connect the PC via Ethernet to the same switch as the NAS at \\YOUR-NAS-IP for the first run, then incremental hourly backups of 1 GB to 5 GB work fine over 5 GHz Wi-Fi. If you must use Wi-Fi initially, go to Control Panel > Power Management > HDD Hibernation > Disable hibernation during backup, and on Windows set Settings > System > Power > Screen and sleep > Never for the first night.
How do I restore if my PC will not boot?
For File History, boot any working PC, map the share via File Explorer > Address bar > \\YOUR-NAS-IP\backup_pcs and copy files back. For a full system restore from Active Backup for Business, create recovery media in advance: On a working PC, open Active Backup for Business Agent > Create Recovery Media > USB or ISO. Boot the failed PC from that USB (press F12 or Del for Boot Menu, select USB), choose Recovery > Connect to NAS at YOUR-NAS-IP with backup_svc, select the latest version, and restore to the internal drive at Disk 0. For Mac, boot with Option + Power, select Time Machine Recovery, connect to Wi-Fi, select the sparsebundle on backup_mac_timemachine when prompted, and restore.
