macOS Network Share Not Connecting — SMB and AFP Fix

What Does This Error Mean?

When your Mac cannot connect to a network share — like a shared folder on another Mac, a Windows PC, or a NAS drive — the error usually says 'There was a problem connecting to the server' or shows a connection refused message. This is caused by network connectivity issues, incorrect login credentials, a firewall blocking file sharing, or a mismatch between the sharing protocols your devices use. Most cases are fixed by restarting the devices involved or re-entering the connection credentials.

Affected Models

MacBook Air
MacBook Pro
Mac mini
iMac
Mac Pro
Mac Studio

Common Causes

The host computer or NAS device is asleep, off, or has changed its IP address
The wrong username or password is being used — Mac network credentials are case-sensitive
The sharing service (SMB or AFP) on the host device is disabled or has crashed
A firewall on the host Mac or on the network is blocking ports 445 (SMB) or 548 (AFP)
Your Mac and the host device are on different network segments or VLANs and cannot reach each other directly

How to Fix It

Make sure the host computer or NAS is on, awake, and on the same Wi-Fi or wired network as your Mac. Try pinging it from Terminal: open Terminal and type ping followed by the host's IP address or hostname and press Return. If there is no response, the host is unreachable.

If the host is a Mac, go to its System Settings > General > Sharing and make sure File Sharing is turned on.
On a Mac host, check that File Sharing is enabled. Go to System Settings > General > Sharing and toggle File Sharing on. Also click Options and make sure 'Share files and folders using SMB' is checked.

macOS sometimes turns off file sharing after an OS update. This is one of the most common reasons a previously working share suddenly stops.
Try connecting manually via Finder. In Finder, press Command + K to open the Connect to Server dialog. Type: smb://[IP address or hostname] — for example smb://192.168.1.100 — and click Connect. Enter the username and password for the host computer.

Connecting with a direct IP address bypasses name resolution issues. If this works but the hostname does not, the problem is DNS or Bonjour name resolution.
Clear the Keychain entry for the old connection. Open Keychain Access (search with Spotlight), find any entries related to the server name or IP address, delete them, and try connecting again. Your Mac may be trying to use old, incorrect credentials stored in Keychain.

After deleting the Keychain entry, you will be prompted for credentials when you connect — enter the current correct password and check 'Remember this password' to save it.
Restart both the Mac and the host device. Networking issues — especially after a host device wakes from sleep — are often fixed by a simple restart of both devices.

NAS devices in particular can get into a state after a long sleep where they stop responding to new connection requests until restarted.

When to Call a Professional

Network share troubleshooting can get complex quickly, especially on business networks with VLANs, Active Directory, or complex firewall rules. If the steps below do not resolve the issue, a network technician can check routing, firewall rules, and directory service permissions.

Frequently Asked Questions

What is the difference between SMB and AFP?

SMB (Server Message Block) is the standard used by Windows for file sharing and now used by most modern Mac and NAS sharing. AFP (Apple Filing Protocol) was Apple's older proprietary sharing protocol. Apple deprecated AFP starting with macOS 11 (Big Sur) and most modern devices use SMB exclusively. If you are connecting to a very old Mac (pre-2015), it may only support AFP, in which case use afp:// instead of smb:// in the Connect to Server dialog.

My Mac connects to the share but it keeps disconnecting. Why?

Frequent disconnections from network shares are usually caused by the host device going to sleep, or by macOS's network timeout settings dropping inactive connections. On the host Mac, go to System Settings > Battery (or Energy Saver) and increase the sleep timer, or turn on 'Prevent automatic sleeping when the display is off' to keep it awake. On your Mac, you can also try mounting the share via an Automator login item so it reconnects automatically at login.

I can see the server in Finder but clicking it gives a connection error. What is wrong?

When Finder discovers a server but cannot connect, it usually means the credentials are wrong or the sharing protocol has a mismatch. First check that you are using the correct username and password for the host computer (not your Apple ID — the local Mac account credentials). If the credentials are definitely correct, try deleting any saved passwords for that server in Keychain Access and entering them fresh. Also make sure the user account on the host Mac has read access to the shared folder.