@Wayne_R  I have the same issue and have contacted support and they act like they don't know anything about it!

  @Wayne_R  This was one of the main features that made me buy this Router. This feature is extremely important for me, now I have to look for an alternative. 

Any updates on this? It almost seems like TP-Link is moving the Archer from being a Router to being an Internet Portal. We have five serious WiFi users and this feature is almost required to untangle what is going on.  Any response from TP-Link?

  @Golding Not an acceptable one.  I was told I could revert back to the previous version of firmware.  I needed to make myself available for a call from China and give them access to my computer.  I give up and will see if I can find some software to monitor usage.

This is one of the reasons I was visiting the site today.

My current setup was ER605 TO the ax6000 however since the update if I use AX6000 in router mode I drop packets and have since had to use it in AP mode. And I'm still not happy. I will likely have to upgrade to a dual wan wifi router and ditch the ER605 and AX6000.. really wish they had a trade in program

This is quite pitiful that this feature was removed!  I "upgraded" to the AX6000 from the C5400X and now traffic monitor has been removed from the Tools menu.  Further, if you look at the firmware release notes, it specifically mentions that you cannot downgrade from the most recent version.

PLEASE fix this and add the feature back because I now have no way of monitoring network traffic to find which device(s) cause bottlenecks and correlate times of slow internet with bandwidth.  This is essential.  I'm not sure why you removed it but my guess is that it must have been causing problems so you just removed it.  Please FIX it instead!