Windows "System error 53" and "System error 5" with net use: the network path, and access denied

C:\> net use Z: \\server01\reports
System error 53 has occurred.

The network path was not found.

Or its neighbour:

System error 5 has occurred.

Access is denied.

They sound similar, but they fail at very different points. Error 53 means you never reached the file sharing service. Error 5 means you reached it, and it refused you. So they lead to different fixes.

Resolve-DnsName server01                     # does the name resolve?
Test-NetConnection server01 -Port 445        # is SMB reachable?
Get-SmbShare                                 # on the server: does the share exist?
net use Z: \\server01\reports /user:CONTOSO\alex *

Error 53: check the path first

A typo gives the same error, and so does the wrong kind of slash. It has to be two backslashes, and no drive letter:

\\server01\reports      # correct
//server01/reports      # wrong in net use
\\server01\c:\reports   # wrong

Then test the name and the port:

Resolve-DnsName server01
ping server01
Test-NetConnection server01 -Port 445

Try the IP address too, as in \\10.0.0.5\reports. If that works and the name doesn’t, it’s DNS. Run ipconfig /flushdns and check the record.

Error 53: the port is closed

SMB uses TCP 445. Each of these blocks it:

• Windows Firewall on the server. The rule group has to be on, for the right network profile:

Enable-NetFirewallRule -DisplayGroup "File and Printer Sharing"
Get-NetConnectionProfile

• The Server service is stopped on the machine sharing the files:

Get-Service LanmanServer, LanmanWorkstation
Start-Service LanmanServer

• A network firewall, a VPN or your internet provider. Many providers block 445 on the internet, and Azure Files users run into this often. To tell blocked from closed, see “Connection timed out” vs “Connection refused”. The Port Lookup explains why 445 should never be open to the internet.

Error 53: an old server

Windows has SMB 1.0 turned off by default, so an old NAS or Windows Server 2003 machine can look like it isn’t there. The real fix is to update or replace that device. See what your client negotiates with servers it can reach:

Get-SmbConnection | Format-Table ServerName, ShareName, Dialect

Don’t turn SMB 1.0 back on without a plan: it’s the protocol the WannaCry ransomware spread through.

Error 5: find out who you are

You reached the server, so it’s about permission. Windows may be sending your current account, not the one you assumed:

whoami
net use

Pass the right account explicitly. Local accounts on the server need its name:

net use Z: \\server01\reports /user:server01\alex *
net use Z: \\server01\reports /user:CONTOSO\alex *

Error 5: two sets of permissions

A shared folder has share permissions and NTFS permissions, and you get the stricter of the two. “Everyone: Full” on the share doesn’t help if NTFS refuses. On the server:

Get-SmbShareAccess -Name reports
Get-Acl D:\reports | Format-List

Add the access to both:

Grant-SmbShareAccess -Name reports -AccountName "CONTOSO\alex" -AccessRight Change -Force
icacls D:\reports /grant "CONTOSO\alex:(OI)(CI)M"

Error 5 for admin shares

\\server01\C$ needs an administrator on that machine. And a local administrator from a remote computer is refused by default: User Account Control filters that account’s rights, unless it’s the built-in Administrator or a domain account. Use a domain admin account if you can, which is much safer than turning that filter off.

Other errors you’ll meet here

For 1219, disconnect the old session first:

net use \\server01\reports /delete
net use * /delete

To see the text for any code, run net helpmsg 53.