@Pairis 

Do you have Deco models other than M5 in your Deco mesh? 

  @Alexandre. Yes I recently added two P9's and reassigned the master status to the new P9.

  @Pairis 

According to TP-Link Support all Deco nodes in Deco mesh must support connection preference feature, otherwise you'll see this error message. 

  @Alexandre. So that means that it is the P9 which is causing the error?

  @Pairis 

It means the fact that you have P9s in your Deco mesh is what causing this error when saving Deco M5 configuration. This sounds illogical, but I know of two other cases with the same end result, so it is not a mistake or fluke.

  @Alexandre. Thanks you for that!

So if you'd allow me to tapp into your brain, to help figuring if the P9 is actually helping me or not.

The old setup.

Ground-floor the master M5 nest to the TV 

First floor M5 wifi connected to the Master

Second floor M5 wifi connected to the 1st floor

This resulted in an unstable connection and both M5's on the 1st & 2nd floor dropped in and out multiple times during the day.

I thought that I could fix this by adding the P9 due to the build in Powerline functionality without the need of pulling cables and drilling holes.

Current setup is

Ground-floor P9 as master on the northside of the house. M5 next to the TV on the Southside.

First floor P9 PLC&Wi-Fi connected to the master

Second floor M5 wifi connection to the garden house

Garden house M5 wifi connection to the Master P9, although the M5 next to the TV is closer located.

The current setup helps because no decos are losing connections anymore. However, the connection between 2nd <-> Garden house & Garden house <-> Master P9 are less then ideal.

Question.

- Is the P9 the right deco for my situation (I can still return it if needed)

- Other solutions that you can think of?

Thanks loads!

Jeff

  @Pairis 

It is obvious that powerline link works for you better than having Deco mesh without it. There are no powerline capable Deco models which support connection preference. Yet, there is another way you could try if you are flexible with buying and returning hardware.

You can force powerline link for Deco M5s using TP-Link powerline adapters. So, return set of P9s you bough and instead buy set of M5s and set of TP-Link powerline adapters. You will have Deco mesh consisting of M5s only. Connection preference feature should work.

Connect Main Deco M5 and First Floor M5 to powerline adapters, and that will make them link through powerline just like P9s did. You can also check if any other Deco M5 will benefit from connecting through powerline adapter.

im also having this problem i currently have 3 m5 and client preference was working before the latest update.i reverted back the firmware prior to the latest update. now its back to normal. the latest update for deco m5 kinda broke the client connection preference. when you set your device to the nearest router it wont connect at all, its still connecting on the farthest router even though the router is beside the device. if you guys have problem just revert to the last firmware hoping they have an update to fix this new bug. 

SHINIGAMI26 wrote

im also having this problem i currently have 3 m5 and client preference was working before the latest update.i reverted back the firmware prior to the latest update. now its back to normal. the latest update for deco m5 kinda broke the client connection preference. when you set your device to the nearest router it wont connect at all, its still connecting on the farthest router even though the router is beside the device. if you guys have problem just revert to the last firmware hoping they have an update to fix this new bug. 

  @SHINIGAMI26 

If you are not getting Error message trying to Save connection preference, you are talking about different issue. If this is the case, it would make sense to create a separate forum topic.