@David-TP 

Hi,

May I know the model number of the 2*( unmanaged ) Gigabit hubs ?    Tp-link TLSG108S  connected to X20  & then connected to the SG108S , a Netgear GS205v2

"also this is the same on all 3 ports of the Deco "--Do you mean the 3*Windows 10 also dropped out when they were directly connected to the 3*LAN ports on Deco X20-4G ?

No, i mean the single Gb connection to the 1st Hub, the SG108S, has been tried on all 3 Gb ports of the Deco

Please set 'Use random hardware addresses' to 'Off' under the Wi-Fi settings of the Windows 10 laptops. 

1)  I did not say i had WIndows 10 laptops, they are desktop PCs

2) i clearly stated that these PCs were cabled Gigabit and that all NON-windows Wifi-connected devices were fine

It is also suggested to temporarily remove the reserved IP addresses on the Deco X20-4G for these 3 laptops.

I already tried this - then re-creating the reservations - as first possible solution.

My system requires reserved IPs but i have had to wrestle with 'co-ordinating' them on my previous Router so i know it's not always by-the-book. However it's only on the Deco that i'm actually losing connections entirely

In theory i could remove the reservations  for the PCs concerned and see if they drop off regardless of what IP they pick up, and i'll 'report' to you result of that.

PS - i did also try setting fixed IPs locally at the PCs as well as the reservations ( same IP )  at the X20, to see if they would  then not drop-off, but this made no difference

Thank you very much and wait for your reply.

  @David-TP 

"  Sorry, and I might have misunderstood your initial post.

Wifi devices always connect to Deco no problem

Wired-LAn NON-Windows devices are always visible/accessible from mobile devices

But the WINDOWS PCs all drop-off the LAN, several times a day, not being re-picked up by DHCP etc., for anything from 5 minutes to hours later. These PCs are all running Windows 10

( also this is the same on all 3 ports of the Deco )

 Clearly the LAN itself on Deco is working per se, but it apparently doesn't like connections to Windows PCs, which is hardly a small problem that can be worked around.

That summary above is correct

Besides removing the reserved address, I have sent a debug firmware via private message for Deco X20-4G_V1.

NB that i removed the IP reservations before and set the IPs manually on each PCs interface. This made no difference to the behaviour

Could you please help me check the following details as well:

1. Could you please let me know how frequently you have encountered this particular issue? Or are you able to reproduce this issue on the LAN desktops in a short time ?

This started as soon as i used LAN to connect to Deco X20 ( previously was hop to an RE505X extender i already had and thence to LAN section )

Normally the LAN drops any of the PCs about 5-10 mins after i start using any of them. 1 x PC is on 24/7 ( media PC ) and this appears connected  each day when i first access it remotely  but after 10 minutes of accessing it  for NPVR recordings from a 'Vero' unit ( non-windows )  the media connection drops because the LAN has. So basically they'll come back 'of their own accord' when i'm not using them, but are almost guaranteed to lose connection after a very short period of active use. This may be Coincidene and i'm just seeing it like that because they drop off every 10 minutes anyway .

 2. Is there any chance that you could connect one of the LAN Windows PCs directly to the Ethernet port of Deco X20-4G and check for a while whether the problem continues?

I could but this is very awkward/disruptive of my whole system, as the nearest PC to the Router is 'headless' and relatively inaccesible so i'll have to move the router instead, not reducing my disdain for this highly expensive yet utterly temperamental product

3. You could save the system log and note down the time when PCs failed to get IP addresses  wi'm not convinced that this will reveal any 'pattern', but this to me is half the point. Usually the PCs GET their IP address when first powered up, so what is 'polling' so that their already-reserved IPs are 'lost' ?