Recent updates for Windows are breaking access to SMB (v2) shares

Recent KB4480970, KB4480968 updates for Windows 7, 2008 r2 server are breaking access to SMBv2 shares.

The fix is a registry entry (run in 'cmd' as administrator):

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

The effect is immediate - no reboot required.
 
Alternatively, install this later Microsoft Update (KB4487345) to fix the problem: