I don't know a whole lot about windows 10.., so grain of salt with me
but, the disk usage going to 100% sounds pretty normal. I would guess that it's just the pagefile being utilized.
The "server execution failed" is probably application specific. Do you generally see it after watching videos or what?
The "clicking" is a little bit more concerning. I've had drives where you can here the spindle click that have lasted for a long time, but usually that's a bad sign, so it's definitely good that you backed everything up. You did say it only happens when you initially access a file, so maybe you're just hearing the spindle moving and your drive is unusually loud. But again, usually when I hear hdd "clicking", I think, uh oh.
(EDIT: If you don't want the 100%, I think there should be pagefile settings you can adjust somewhere)
Regarding the clicking sound, it only clicks once, after that, i would not hear it unless i reboot the system.
Pagefile options did not give me any immediate answers, so i guess it could be something else (i already disabled power savings, in case people wondered, so it does not turn of every x minutes)
The "server execution failed" error only comes after the 100% "bug" is going away, otherwise, it never shows up.