Microsoft’s Win7 Monthly Rollup and Security patch KB 4480970 causes headaches for businesses in the New Year. The update, which was released on January 8th 2019 caused serious network issues for Windows 7 SP1 & Windows Server 2008 R2 SP1. Network shares were inaccessible via SMB2v2 under certain conditions. 

Infusion IT has recently fixed this issue for one of our clients who experienced problems accessing network shares. Our client could access the share via the IP address but not via the NetBIOS name. At the moment the only two fixes are to either, remove KB 4480970 or apply a registry fix. See below: –

reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\system /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 1 /f