Loss of DNS access to shares after 5.31.102 update

Many users of Western Digital My Cloud NAS devices have recently reported a troubling issue: after updating to firmware version 5.31.102, access to network shares using DNS/hostname resolution (e.g., \\mycloudex2ultra) stops working. While direct IP-based access (e.g., \\192.168.1.100) still works, users are unable to connect using the NAS hostname. This issue can be frustrating, especially for environments relying on consistent UNC paths or mapped drives.

This article explores the possible reasons behind this DNS issue and offers proven solutions to restore hostname-based access to shares.

What Changed in 5.31.102?

Firmware version 5.31.102 introduced several stability, security, and service changes. However, it also appears to have affected how the NAS handles NetBIOS name broadcasting and mDNS (Multicast DNS) services, which are essential for hostname resolution in local networks. Some users noted that after the update:

Hostname no longer resolves via Windows Explorer

Mapped drives using DNS names fail to reconnect on boot

The device is no longer discoverable under the Network section of Windows File Explorer

ping <NAS-name> fails or returns an error

Possible Causes

NetBIOS and SMB Browsing Changes:

WD may have disabled or altered how NetBIOS name announcements are broadcast. This impacts Windows devices that rely on SMB 1.0/NetBIOS for device discovery.

Multicast DNS Disabled or Broken:

mDNS (Bonjour/Avahi) may be malfunctioning or disabled, preventing macOS and some Linux systems from resolving .local hostnames like mycloudex2ultra.local.

Windows SMB Discovery Broken:

Modern Windows versions (especially Windows 10 and 11) have deprecated SMBv1, which also removed automatic network discovery in some setups.

Router DNS or Local Network Cache Conflicts:

Your router may fail to update its internal DNS mappings after the NAS firmware update.

Fixes and Workarounds

✅ 1. Use Static IP and Local Hosts File (Quick Fix)

Assign your NAS a static IP from your router, then manually map it using the hosts file:

On Windows:

Open Notepad as Administrator

192.168.1.100 mycloudex2ultra

Save the file, then access via \\mycloudex2ultra

✅ 2. Access via IP Address

While less ideal, use \\<IP> in File Explorer or remap network drives using the IP address.

✅ 3. Enable SMBv1 Temporarily (Caution)

Re-enable SMB 1.0 via Windows Features only if absolutely necessary, and only on trusted networks.

✅ 4. Reboot Devices and Router

Restart your NAS, PC, and router to flush DNS and NetBIOS caches. This may help rediscover the NAS.

✅ 5. Wait for WD Fix or Roll Back Firmware

If the update introduced this issue, WD may release a hotfix. You can also contact support to request a firmware rollback—though this is not officially supported in most cases.

Conclusion

The 5.31.102 firmware update for WD NAS devices appears to interfere with local DNS/NetBIOS resolution, breaking hostname-based access to shares. While a full fix may require a WD patch, workarounds like editing the hosts file, using IP addresses, or adjusting SMB settings can restore functionality in the meantime. For users in production environments, testing firmware updates before widespread deployment is advised.