Devices showing up within Network in Windows File Explorer but not in wireless router or access list

[MoritzTheCat]

When I open Network in Windows File Explorer lately I'm sometimes seeing a Samsung Galaxy tablet and an Epson printer that I don't own show up there.

After I first noticed this, I turned off Bluetooth on the PC, but they're still showing up. I do not have a Homegroup. The network is setup as Private. Windows Defender Firewall is On.

I ran anti-virus scans and Malwarebytes scans on all of my connected devices and no threats were found.

I also looked at my wireless router setup. I have a NetGear WNDR4000 using WPA2-PSK [AES] as the only security option and a 21 character passcode that I have not shared with anyone. About a week or so ago, there was a firmware update available that was applied to the router direct from NetGear. I also have a MAC address based access list turned on in the router. The MAC addresses of these "phantom devices" are not in this access list.

When I have seen these devices appear, I've gone into the router setup and they do not show up as being connected to the router. If this is the case, I don't understand why they show up as devices in the Network in Windows File Explorer.

As I'm writing this, the printer and the tablet dropped off the Network view; the tablet reappeared after a few minutes and is now gone again. I suspect they're nearby in one of the neighbor's houses, but I don't understand why they show up on this list.

I'm stumped. If someone could please provide an explanation for this, I'd be very grateful. Thanks!

[MoritzTheCat · Accepted solution]

I can't explain what was going on in the Network view of File Explorer with my old wireless router, but I solved the issue with $.

I bought a new router. After the last firmware update (probably to address the KRACK issue), the router was slower and I was not getting the top speed from the cable modem unless I was connected directly to the modem or hardwired to the router. I was also previously having sporadic issues with the WNDR4000 that meant having to restore backed-up settings to get it to function again. So I took all these clues as a signal that after 5 years, it might be time to invest in a new one.

I initially purchased a Linksys EA6700 (since it was quite a bit cheaper), but after fighting with it for 4 hours and not being able to connect any of our 5GHz devices, I gave up and returned it to Best Buy the following day. Exchanged it for a Netgear Nighthawk R7000 and had all 12 of our 2.4GHZ and 5GHZ devices connected within 15 minutes. For the most part, I was able to duplicate the setup from the old router to use with the new one.

It's been two weeks and not a single hiccup or any downtime. Much better coverage/signal strength throughout the house versus the WNDR4000. 

Also, I'm not seeing any more phantom devices in the Network view of File Explorer, so I think the old router was to blame. Writing this prompted me to backup my router settings and stash a copy in a few places. Case closed!