access to a network drive by a win10 user

It's possible that this PC sees the network as public rather than private. In that case, it won't be able to access local network resources, whether self-advertising or shared. You can check your network status by clicking the wired or wireless networking icon in the notification area of the taskbar. You'll see something like this:

Notice the word "Private" in front of network. If yours says "Public" instead, you need to change that over. To do that, click "Change connection properties" then click the radio button next to Private under the Network profile heading at the top of the resulting pop-up window. You'll need to confirm that selection in the notification center, and then you should be good to go.
HTH,
--Ed--

PS: I had this happen to several of my Win10 Pro and Enterprise installations immediately after upgrading to the Fall Creator's Update, and have dealt with this on other, previous upgrades. Thus you might be in the same situation. It's easy to check, and easy to fix, fortunately.

Ohhh.... lightbulb goes off .... that means it's an account issue. It may be easiest (and fastest) to create a new account for the problem account and migrate the files, then migrate or recreate its settings and preferences. Here's a discussion from answers.ms.com on how to do this: Transfer of settings and files between user accounts - Microsoft Community.
HTH,
--Ed--