Microsoft’s September 2025 Windows security updates cause connection issues with SMBv1 shares across multiple platforms. Microsoft is working on a fix and recommends a temporary workaround involving TCP port 445. #SMBv1 #WindowsSecurityUpdates
Keypoints
- The September 2025 updates create connectivity problems with SMBv1 shares on various Windows platforms.
- This issue affects both client and server editions, including Windows 11, Windows 10, Windows Server 2025, and Windows Server 2022.
- The problem occurs when either SMB client or server has the latest security update installed.
- Microsoft advises temporarily allowing TCP port 445 traffic to bypass NetBT-related connection failures.
- SMBv1 protocol is outdated, deprecated, and known for its security vulnerabilities, including exploits like EternalBlue used in major malware attacks.