Internet crashes when attempting high-speed transfer to MyCloud

I’m having trouble writing to MyCloud.
First I tried copying files from an older laptop without gigabit adaptor (hence using slower 2.4 GHz connection to my router) and this worked fine though only getting speeds of 3-5 MB/s. Then I tried using my PC with gigabit adaptor, using the 5 GHz connection. This gives me speeds averaging 30 MB/s but after a short time (sometimes seconds, sometimes 3 minutes) the internet disconnects and I get a “0x8007003B unexpected network error”. Some files gets copied over but not many before it crashes. I have no problems with my internet otherwise. This is what I’ve tried so far:

(1) switched off windows firewall
(2) switched off anti-virus
(3) disabled Teredo Tunnelling Adaptor (- read this solved similar issue for some people)
(4) static IP
(5) port forwarding (via WD interface and Router settings)
(6) using 2.4 GHz on my PC: no disconnection but internet unusably slow for any other devices, even those on 5 GHz connection!

Since I changed to a static IP my router’s browser-interface no longer shows the MyCloud as a device however I can access the device fine using file explorer or via the IP address in a browser.

Run out of ideas now so any help would be appreciated please!

Mike

Tested on my work laptop which uses the same 5 GHz connection and this completes large transfer perfectly, no disconnection and constant speeds of approx 35MB/s. Also using my PC (the one I’m having the problems with) to write to an old My BookWorld device, this works fine albeit at a slower 13MB/s (and reasonably constant speed).
So could it be some conflict between MyCloud and my PC’s TP-Link 802.11ac Network Adaptor?

(By the way, I have no Bitdefender on my PC, have latest driver and firmware for MyCloud and router, I’ve tried changing internet channel, tried FTP transfer, and tried SMB1 in case that makes any difference).

Any help would be greatly appreciated.

should have mentioned that Work laptop is Windows 7, PC with problems is Windows 10.

Hello,

I recommend you email WD support about this.