100% cpu almost permanently

my ex2 has cpu almost permanently at 100%. Nothing is backing up to it. Impossible to browse to it as takes ten minutes to load menus. Earlier, copying files from internal storage to attached usb drive was impossible as transfer rates were 10 KB/s (yes, I said KB). Device effectively unusable

Check the process list to see what’s using so much.

Any chance that you are using their antivirus software?

Mine did that when clamAV was on. If you are using, consider to uninstall the app.

no antivirus installed, no response from western digital support, will buy buffalo nas instead, fed up with western digital

The 10 % in the post was a typo ?

Still would be interesting to see the cpu process list.