Windows 11 can’t see/map NASes, manufacturer’s software confirms they’re attached

Troubleshooting NAS Connectivity Issues on Windows 11: A Case Study with Synology Devices

In the evolving landscape of network-attached storage (NAS) and modern PCs, connectivity issues can be a common source of frustration. This article delves into a real-world scenario where Windows 11 fails to recognize or map Synology NAS devices, despite the manufacturer’s software confirming their proper connection. Through detailed analysis and troubleshooting steps, we aim to provide a comprehensive guide for users facing similar challenges.

Understanding the Scenario

A recent PC build running Windows 11 was connected to two Synology NAS devices:

• Synology DS220j configured as Just a Bunch Of Disks (JABOD)
• Synology DS223j configured in RAID 1

Both NAS units were initially accessible via mapped network drives in Windows, with folders appearing as expected. However, after approximately a month of normal operation, the network drives suddenly displayed as offline, prompting investigation.

Initial Symptoms and Observations

• File Explorer shows the mapped drives as offline.
• Clicking on the drives or network reveals the NAS devices, sometimes appearing and disappearing intermittently.
• Attempting to reconnect or remap drives results in errors such as “The local device name is already in use” and “Windows cannot access \\SYN_NAS_223\Photos” with error code 0x80070043.
• Synology Assistant successfully detects both NAS units, and the DSM management interface confirms they are healthy and accessible.
• The NAS devices are visible and accessible via their web interfaces and Synology’s File Station.
• The old Windows 10 machine connected to the same network maintains stable connections, indicating a potential Windows 11-specific issue.

Network Environment Details

• The network comprises two Netgear GS308 switches, each with dedicated cabling.
• NAS devices are connected to one switch, separate from other devices like printers, smart TVs, and wired access points.
• The setup is a self-built PC with recent hardware specifications, including an Intel Core i5-13400F processor, MSI motherboard, and high-speed SSD.

Troubleshooting and Testing Steps

1. Verified NAS Functionality: Confirmed through Synology Assistant and DSM that NAS devices are operational and accessible.

2. Checked Network Visibility: Noted intermittent appearance of NAS devices in the Windows “Network” section, suggesting possible network discovery inconsistencies or Windows 11 quirks.

3. **Test