@David-TP 

Thanks for the swift response.

I didn't set the DNS settings, they have come from the dynamic IP settings generated by the VM modem.

My LAN settings were in the original post

My LAN IP is 192.168.1.1 and DHCP range set to 192.168.1.2-192.168.1.254

Subnet mask is standard 255.255.255.0

When the problem occurs the LAN IP changes to 192.168.0.1

When I first got the Deco, it was set to 192.168.0.1 but this issue occured and began changing the LAN IP to 192.168.1.1. I didn't realise it was going to be a recurring issue so stuck on the 192.168.1.1 range. Now it just does the opposite when power fails.

Thank you

This is killing me.

I'm trying to setup smart wall socket devices which my Deco & VM modem are connected too.

To set them up you need to power cycle the smart wall socket.

I have connected the Deco to a separate power supply and kept the modem running. Even when I keep the device running, the Deco is resetting the Lan IP to 192.168.0.1 when the Modem reboots.

This makes the remaining smart devices lose their connection and I'm back to square one. I have wasted days and days of my life with this ridiculous issue.

I have spent over £500 on 5 Deco M9s. I am so dissapointed in this lack of basic functionality and stability. What is the point in owning these??? My wife and family are giving me so much stick over this I'm at the point where they're going to have to be binned.

TP-LINK - W*F is going on here. Sort. It. Out!

  @solderchicken 

There is some sort of conflict between your home network IP range and IP addresses of your DNS servers, that Deco mesh tries to resolve and messes up.

If you can't change DNS IP addresses, select different IP range for your home network, for example 172.16.0.2 – 172.16.0.255, and see if problem goes away.