I install these devices for a living and have installed at least a dozen M5 Mesh systems for client. For the most part it goes very smooth. However, TPLink Deco 5 APP has a very big problem when the client has a combo modem/Router.

In this case you cannot create a network and you need to change the operation mode to Access Point. But you can't do that until the M5 is online with the the Modem/Router.

What is worse, the M5 retains the SSID it acquired when the mandatory network was set up. This defeats the purpose of creating an access point: No need to reset all devices with new SSID and passwords.  

So, IMO, here is what should change:   At the point where the App now insists that you create a network it should offer the Operational Mode choice. Once in Access Point mode all else gets easy. 

I have too many extra hours fighting this issue.  If anyone has any influence on the TP-Link software guys please forward this request.

Ken Wood

Camarillo CA