Microsoft has overnight pushed out the latest of its ongoing preview builds for Windows 10, with this one carrying a warning that it could break your network file share connections.

Redmond-watchers will know that the firm runs a Windows Insider programme where users can sign up to be guinea pigs get early access to features and changes that will be delivered as part of its work-in-progress operating system at a later date.

The latest of these, Preview Build 14936 – for testers on what Microsoft refers to as the Fast Ring – comes with the usual set of updates, new features, and fixes for things that the previous release managed to break.

However, what caught our eye was a warning that after updating, users may find that shared devices such as NAS boxes have mysteriously disappeared from the home network folder, and that any previously mapped network drives are unavailable.

Microsoft offers a fix for this; if you change your network to “private” or “enterprise”, it should start working again.

It seems that the cause of this hiccup is a fix that Microsoft made earlier in September to address a security hole severe enough that it might allow remote code execution with elevated permissions on an affected system, although this would require an attacker to create a specially crafted request.

The fix addresses this by, among other things, “correcting how Windows enforces permissions”.

Windows Insiders are typically no newbies and used to preview builds breaking stuff, but it is likely that this change will find its way into the Windows 10 code everybody else is running sooner or later.

In addition, the vulnerability affects older versions of Windows going back to Vista, so bear this in mind if your network shares disappear after you install some Windows updates in future.

Those interested in more detail can read through the relevant Microsoft Security Bulletin.

Meanwhile, Preview Build 14936 adds a few new extensions for Microsoft Edge and prepares the way for an update to the Windows Subsystem for Linux (WSL) in Windows 10 to use Ubuntu version 16.04 instead of the older Ubuntu 14.04. ®