@Pip60 

Do you see powered off (unplugged) Deco in Deco app as OFFLINE, or do you not see it in Deco app at all?

  @Pip60 There are two devices in offline clients one is a network device and the other is an unknown device but its not either of those. It only shows under owner along with the one thats the main deco.

  @Pip60 

It will not be in "Offline clients," that list is for devices connected to Deco mesh.

I powered off one of my Deco M5, named Study, this is what I see in Deco app:

Do you see your unplugged Deco on that page in your Deco app? If not, please share screenshot of that page from your Deco app.

  @Alexandre. Thats not what i mean at all. Under my account i click on owner it shows two decos one connected as main deco and the other not connected. So until i can get rid of the unconnected one i cnat use that deco at all.

  @Pip60 

Follow this document, section Reset a Deco unit: How Do I Reboot or Reset My System?

  @Alexandre. That wont help i have already rebooted network plus the deco i want to delete is not even connected it has been in its box for weeks. I have had trouble with TP link for weeks now devices just take themselves of line even when they are not and show as online when they have been offline for hours. At the moment the phone i have with app on is currently offline according to Deco App.

  @Alexandre. Thank you that worked.