Microsoft has doubled down on efforts to persuade users to migrate to Windows 10 by breaking Windows 7 networking for some.
Windows Server 2008 R2 is also affected.
While the last few monthly updates for the soon-to-be-obsolete OSes featured a known issue affecting an "unknown" number of "problematic configurations" that require manual reinstalls of network drivers, January's monthly update seems to have upped the ante somewhat.
2019's treat has seen some users finding their shares are now inaccessible, with RDP and other connectivity also suffering.
The issue, which affects both the bonzer monthly roll-up (KB4480970) and the more petite Security-only update (KB4480960, which has no known issues according to Microsoft at time of writing), leaves users receiving an INVALID_HANDLE when attempting to kick off a SMB2 connection.
A bit of sleuthing by a contributor posting on Administrator.de has pointed to the problem being related to Microsoft tweaking security settings in the update, with administrators on the host system being affected.
The post by "Andi" at Administrator.de reckoned it was down to "an extension of security".
This is of scant comfort to users who have had to back-out the patch to get connectivity up and running again. After all, there is important stuff in those updates that really needs to be installed.
The Administrator.de contributor suggested a possible solution, requiring a Registry change around Admin credentials.
Users have reported success, but The Reg has been unable to check it out for ourselves, so try it at your own risk. The usual health warnings apply: fiddling with the Registry could leave your system irrevocably borked.
Others have opted to uninstall and await an official fix to be emitted by Microsoft.
We contacted the Windows giant to find out when such a fix might be forthcoming, but have yet to receive a response.
In the meantime, a Reddit thread has popped up with users discussing their own experience of Microsoft's latest quality cockup, with one wag observing: "We are their QA and I think we do a fantastic job of finding problems. Just not pre-release."
Thanks to eagle-eyed Reg reader Mark Fell-Crook for the tip