@ccrapp I had similar setup to what you will: ISP router with external drive connected to USB3 port, and Deco mesh running in AP mode. Everything worked just fine: external drive and ISP router were...

@Eric1067 Someone else had a similar issue I tried to help with, and as strange as it may sound, at the end they said replacing Ethernet cable which goes to affected Deco fixed the problem. See...

@wizzardlizzard Check if IPTV feature got enabled in your Deco mesh. If it is enabled, see if you can disable it. More about that feature here: How to Configure IPTV function on Deco

@Juzcat Do you have ISP modem or ISP modem/router? If it is just modem, what did you use for router before Deco mesh?

@ccrapp If you are not on very tight budget, I would recommend to go with M4 instead of E4. You might not need gigabit Ethernet ports now, but you are buying Deco mesh to run it for few years. What...

@Farzadk85 I would suggest you review the following TP-Link FAQ: General questions about Ethernet Backhaul feature on your Deco Answering your questions. 1. The positioning of Deco units is still...