The samba service is running and working on the NAS, and I can get the list of shares via a Linux machine with smbtree - none of which is a surprise, nothing changed on the NAS, it's Windows that's broken.

I can ping the NAS and connect to its web-based GUI so it's not a general network issue, it's something specific to accessing the CIFS shares.

Searching is useless - I'm getting nothing on how to pinpoint what the issue is on Windows. (There's a billion answers for Linux but I know that side is working.)

I did change networks stuff a couple of weeks ago for an unrelated issue (think I turned off IPv6 and probably other stuff I can't remember), and whilst I think I used the NAS since then I can't remember for sure.

I've turned IPv6 back on and been fiddling with HomeGroup stuff because that's related to file sharing, though I don't think I was in a HomeGroup before.

Any ideas what to try?

Though the error dialog does come up straight away with the IP - using the hostname it takes a while (though it's in my hosts file so not sure why there'd be a difference).

C:\Users\Peter>net view \\169.254.184.206
System error 53 has occurred.

The network path was not found.

C:\Users\Peter>ping 169.254.184.206

Pinging 169.254.184.206 with 32 bytes of data:
Reply from 169.254.184.206: bytes=32 time<1ms TTL=64
Reply from 169.254.184.206: bytes=32 time<1ms TTL=64
Reply from 169.254.184.206: bytes=32 time<1ms TTL=64
Reply from 169.254.184.206: bytes=32 time<1ms TTL=64

Ping statistics for 169.254.184.206:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

1) if it is domain environment, check your WINS;
2) if it is peer-to-peer workgroup, enable NetBIOS over TCP/IP;
3) make sure the machine is running;
4) make sure file and Printer Share enabled on remote computer;
5) make sure client for ms networks is enabled on local computer;
6) make sure you type the correct name.
7) Make sure no firewall running or any security setting.

1 doesn't apply, 2 didn't work, 5 is enabled, toggling firewall made no difference.

I'm currently thinking it's got to be something in Local Area Connection Properties and/or TCP/IPv4 properties - something I inadvertently changed and whatever configuration I try I can't find the magic values that it had before. :(

Network discovery is on.

Windows IP Configuration

   Host Name . . . . . . . . . . . . : Storm
   Primary Dns Suffix  . . . . . . . : 
   Node Type . . . . . . . . . . . . : Mixed
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter Wireless Network Connection:

[snip]

Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 00-90-F5-9B-5A-57
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Autoconfiguration IPv4 Address. . : 169.254.184.205(Preferred) 
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 
   NetBIOS over Tcpip. . . . . . . . : Disabled
   
[snip]

Accessing NFS shares on Windows seems like a minefield, and there's an iSCSI option but that seems to have so much configuration... :&

So if I can't figure out WTF is stopping CIFS connecting then that leaves me with FTP. :'(

Regrettably I don't know of any protocols that possess the appropriate temporal aspect to let me record all the settings and changes made before things got screwed up.

The NAS is connected via Ethernet to the same switch as the Windows machine. (The NAS doesn't connect to wifi.)