My neighbour brought his brand new Synology over one Saturday, convinced the box was faulty. It powered on fine, the web interface loaded, but Windows flat out refused to show the shared folder. Nothing wrong with the hardware at all. The SMB service simply had not been switched on, and the two machines could not agree on which version of the protocol to speak.
That single afternoon covers about 80 percent of the file sharing problems I get asked about. So let me walk you through the whole thing properly, from enabling the service to mapping the drive on both Windows and Mac, and then the fixes for when it stubbornly refuses to appear.
What SMB actually is, in one paragraph
SMB stands for Server Message Block. It is the language Windows has used for decades to share files across a network, and both macOS and Linux speak it too. Your NAS runs an SMB server, your computer runs an SMB client, and when they connect a folder on the NAS shows up as if it were a local drive.
The catch is that SMB comes in versions. SMB1 is ancient and full of holes. SMB2 and SMB3 are the modern ones you actually want. If you want the technical background, the Server Message Block overview on Wikipedia lays out the history clearly.
Step 1: Turn on the SMB service on your NAS
This is the step my neighbour skipped. Nothing works until the SMB server is running.
On a Synology box, open DSM in your browser, go to Control Panel, then File Services, then the SMB tab. Tick Enable SMB service and hit Apply. On a QNAP, it lives under Control Panel, Network and File Services, Win/Mac/NFS/WebDAV, and the Microsoft Networking section. On TrueNAS, you enable the SMB service under Services and set it to start automatically.
While you are on that screen, look for the advanced or protocol settings. Set the minimum SMB version to SMB2 and the maximum to SMB3. That range keeps things secure and fast while staying compatible with every current Windows and Mac.
Step 2: Create a shared folder with the right permissions
A running SMB service is useless without a folder to share. On Synology this is Control Panel, Shared Folder, Create. Give it a plain name with no spaces, like media or backups. Spaces and odd characters cause weird path problems on older clients, so I avoid them out of habit.
Now the part people rush and regret. When you create the folder, you assign which users can read and write to it. Create a dedicated user account for yourself if you have not already, give that account read/write on the folder, and leave the guest account disabled unless you have a specific reason.
Step 3: Find your NAS address
To map the share you need to know how to reach the NAS. You have two options, and one is far more reliable.
The IP address is the sturdy choice. Find it in your NAS dashboard, usually something like 192.168.1.50. Better still, log into your router and set a DHCP reservation so that address never changes. A NAS that jumps to a new IP after a reboot is the cause of countless mystery disconnects.
The hostname, for example the name you gave the box like NAS or DiskStation, is friendlier but flakier on Windows because it relies on name resolution that does not always work. I reach for the IP first and only fall back to the name.
Step 4: Map the drive on Windows
Open File Explorer, right-click This PC, and choose Map network drive. Pick a drive letter, then in the Folder box type the address using backslashes:
192.168.1.50media
Tick Reconnect at sign-in so it comes back after a reboot, and tick Connect using different credentials. When the login box appears, enter the NAS username and password you created, not your Windows account. Tick Remember my credentials and click OK.
If it connects, the folder opens and a new drive letter appears under This PC. That is the whole job on Windows when everything cooperates.
Step 5: Connect the share on a Mac
Macs handle this through Finder. Press Cmd+K, or use the Finder menu Go, then Connect to Server. In the box, type the address with forward slashes and the smb prefix:
smb://192.168.1.50/media
Click Connect, enter your NAS username and password, and tick the option to remember it in your keychain. The share mounts and shows up in the Finder sidebar. To have it reconnect automatically at login, add it under System Settings, General, Login Items.
When it will not connect: the real fixes
Here is where most of my inbox lives. Run through these in order.
Windows cannot see or reach the NAS
The classic error is 0x80070035 The network path was not found. Nine times out of ten this is a version or discovery problem, not a broken NAS.
| Symptom | Likely cause | Fix |
|---|---|---|
| NAS missing from Network list | Network discovery off | Type the IP path directly instead of browsing |
| Error 0x80070035 | SMB version mismatch | Set NAS min version to SMB2, reboot both |
| Login rejected repeatedly | Wrong account used | Use the NAS username, not your Windows login |
| Drive vanishes after reboot | NAS IP changed | Set a DHCP reservation in the router |
Do not solve a version mismatch by turning SMB1 back on. Fix it on the NAS side by allowing SMB2 as the minimum. Microsoft explains the security reasoning behind the SMB1 removal in Windows, and it is worth trusting them on this one.
Mac connects but is slow or drops out
On macOS, an occasional culprit is the little hidden files the system writes to network shares. A cleaner fix for chronic drop-outs is to make sure your NAS advertises itself over Bonjour, which most consumer boxes do out of the box. If a share keeps unmounting, reconnect via smb:// with the IP rather than the hostname, and the stability usually returns.
Everything looks right but access is denied
This is almost always permissions. The folder exists, the service runs, but the user account you logged in with does not have read/write on that specific folder. Go back to the shared folder permissions on the NAS and confirm your account is listed with the access you expect. A user can exist on the NAS and still have zero rights to a given share.
A quick word on backups over SMB
Plenty of people point Windows File History or Mac Time Machine at an SMB share. It works, and it is convenient. Just remember that a share on the same network is not an offsite backup. If you want the reasoning on why one copy is never enough, this explainer on the 3-2-1 backup strategy from Backblaze is a solid ten-minute read.
Where this leaves you
Get the four fundamentals right and SMB rarely gives trouble again. Enable the service, set the version range to SMB2 through SMB3, create a folder with a real user account holding proper permissions, and pin the NAS to a fixed IP.
My neighbour's DiskStation was mounted and copying photos within twenty minutes once we stopped fighting the symptoms and enabled the service he had never switched on. Do those four things up front, and you will spend your weekend using the NAS instead of debugging it.
Frequently asked questions
Why can Windows not find my NAS even though it is powered on?
The most common reasons are that the SMB service is not enabled on the NAS or that network discovery is off in Windows. Skip browsing the Network list and type the address directly as \192.168.1.50sharename. If you get error 0x80070035, it is usually an SMB version mismatch, so set the NAS minimum version to SMB2 and reboot both devices.
Should I enable SMB1 to fix a connection problem?
No. SMB1 is insecure and Microsoft disabled it by default for good reason. Instead, fix it on the NAS by allowing SMB2 as the minimum protocol version. Any current Windows or Mac speaks SMB2 or SMB3, so you never need the old version.
What is the difference between mapping by IP address and by hostname?
An IP address like 192.168.1.50 is the more reliable target because it does not depend on Windows name resolution, which often fails on home networks. A hostname like DiskStation is friendlier to read but can be flaky. Use the IP, and set a DHCP reservation in your router so the address never changes.
Why does it say access denied when the folder clearly exists?
This is almost always a permissions issue on the specific shared folder, not a broken share. Confirm your NAS user account is listed with read/write access on that exact folder in the NAS settings. If that looks correct, clear the saved login in Windows Credential Manager, because stale passwords trigger the same error.
Can I use an SMB share for Time Machine or Windows File History backups?
Yes, both work over SMB and it is a convenient local backup target. Just keep in mind that a share on the same network is not an offsite backup and will not protect you from theft, fire, or ransomware that reaches the NAS. Pair it with a second copy stored elsewhere.
My mapped drive disappears every time I reboot. How do I stop that?
Two things fix this. Tick Reconnect at sign-in when you map the drive on Windows, or add the share to Login Items on a Mac, and set a DHCP reservation for the NAS in your router so its IP address stays constant. A changing IP is the usual reason a saved mapping breaks after a restart.
