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Accepted
Daniel
Asked: 2017-10-12 07:37:35 +0800 CST

Windows 10 Pro workstation can no longer access Synology File Share

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Note that I have also cross posted this to Synology forums. I'm posting here because I'm not sure if the problem is with Windows or with the Synology server:

Background

Dozens of workstations with several Synology servers.

All workstations running Windows 10 Pro.

For the past year, and up until about a week ago, all workstations were able to access all Synology servers fine.

Problem and Symptoms

Now just starting about one week ago, ONE workstation is unable to access ONE Synology server via Windows Explorer.

It doesn't work with \\UNCname nor with \\ip.ad.re.ss

However, I can ping the server just fine using the ip.ad.re.ss and nslookup for UNCname returns the correct address.

Conundrum

If this were happening to all my workstations, I'd assume the Synology server was at fault. But all the other workstations have no problem accessing this one Synology box. If this were happening with all Synology servers on this one machine, I'd assume the workstation was at fault. But the workstation has no problem accessing the other Synology boxes on the same network, and up until a week ago had no problem with the specific box in question.

Again, it is just the ONE workstation suddenly having problems with ONE Synology server.

Nothing has changed on my end, except of course that there are automatic updates for both Synology and for Windows 10... so again I have no idea where the problem lies.

file-sharing

4 Answers

  1. Best Answer

    There are a number of things you can check... that might give you more insights into what is going on.
    Ping can be a useful tool, but can also give you many false-positives.

    • Have you looked at the arp table and made sure that the mac-address matches the device? Maybe something else has hijacked the mac-address, or a duplicate IP in the network.
    • Are you dropping any packets? Maybe you have a bad cable or ethernet port (on switch or device).
    • Have you compared the subnet mask? maybe you have the wrong mask, and are outside the subnet.
    • Have you tried connecting to other network shares? Maybe there is something borked with the network stack on that machine.
    • Have you looked at the windows firewall? Maybe it is blocking access to the device because you are in a "public" zone instead of "domain" or "private".
    • Have you tried connecting to other services on the synology? ... last I checked, they also respond to http/https? Maybe being able to connect to other ports on the device might give you additional info.
    • Have you updated network drivers on that device? Perhaps you're using an old broken driver.

    ... the list continues.

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  2. For this exact situation, I solved it by going to "Turn Windows features on or off" and ensuring that all three options under "SMB 1.0/CIFS File Sharing Support" were checked.

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  3. I suppose that the Windows 10 Pro computer can open the DSM website of the culprit Synology in a browser (http://ipaddress:5000 or https://ipaddress:5001), but fails to connect to the Synology fileshare in Windows Explorer?

    What is the mininal and maximal SMB protocol set in the Synology box (Control Panel > File Services > SMB/AFP/NFs tab > Advanced Settings? Any other Advanced settings out of order, compared to the other Synologies?

    Something to look at: years ago it was necessary to lower the Windows NTLM authentication on the workstation to a less secure level to be able to connect to a Synology fileshare using Windows Explorer. I can't find the specific settings for now, but google for it.

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  4. Thanks to @TheCompWiz, using net use from the command line gave me a more detailed error message, indicating that Windows could not access the share for security reasons as SMB1 access is deprecated and the server was only allowing SMB1 connections (not sure why). After changing the server settings to allow SMB2 connections, the problem was fixed.

    I'm also not sure why I only had this problem on one machine and only one user, and all other machines were able to access the share with no problem when they are all running the latest version of Windows 10 Pro. But I'm not going to worry about that right now - everything is working fine.

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