Access issues after upgrade to Win10 V1803 (I think it's a Windows issue, not a NAS one).

OK.  So in the last week, Microsoft has upgraded my three Windows machines (two desktops and a laptop) to V1803.  After the upgrade, only one of the desktops is acting strangely.  All three machines are Win10 Pro, and the two desktops are plugged into the same switch.  I know none of this is a ReadyNAS problem, but I tend to get a lot better help here than on the Microsoft forums (where cluesless users add useless advice and the Microsoft reps always seem to want to blame the user).  All of this (except as noted) is new after the Windows upgrade and none of them occur on the other two machines.  The NAS is on OS6.9.2, but it's hard to believe that's an issue since the other computers have no problems.

I cannot access my NAS by Name (RN516A), but can via IP address.  RN516 shows up under "Network", but clicking on it opens a blank window and after a long pause, Windows says is cannot access \\RN512A and suggests I check spelling, etc.  Before I changed them to use the IP address, my mapped drive letters did the same.  If I turn on my backup NAS, it behaves the same way.  It doesn't even prompt for a password.  The very first time I tried to access the backup, Windows did prompt for a password.  That may have happened on the primary as well and I just don't remember.  NET VIEW \\RN516A also cannot find the path and gives a system error 53..

I deleted all mapped drives (net use * /delete), remapped them using the NAS IP address, and I can again use the mapped drives.  But when I go to move a file, I get a Windows security warning that my internet security settings suggest that one or more of the files may be harmful and I have to click OK for every single file.  The backup unit has no mapped drives.

This is the only thing I don't know wasn't there before, but I suspect it wasn't because I had no drive mappings using the NAS IP address.  NET USE shows me an undesignated (no drive letter) connection to 192.169.0.42\IPC$.  That is my NAS's address, and Microsoft says this is the "Interprecess Communications Share", apparely linked to anonomous users, even though I never use anonomous access.

I have done the NET USE * /DELETE.  I have verified there are no credentials in the credentials manager for the NAS (there never have been).  I have rebooted the PC and NAS several times.  I've lowered user account control (though it was not changed).  I've diabled my security software.  In case it maters, the login name on all PC's is the same on all PC's and the same as my NAS account.  Windows password is the same on all PC's but not the same as NAS password, so password prompt has always appeared when accessing the NAS.

Any suggestions?  I've got things mostly workng except for that damned security prompt, but I'd like to get things back to normal.  And I'd especially like to know why the \IPC$ connection is there and why it remains (though "disconnected") even when the NAS is off.