You can remove the policy that's preventing you from changing the settings in gpedit.msc
or if your not running a pro version of win 10 just look for it in the registry i would start looking in
"[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies]" and similar locations
Chances are that Window 10 already has the drivers so you might not see the new hardware notification.
Right click on the start menu button select "Disk Management" from the popup menu
Check to see if the external drives are there.
If they are there but don't have Drive Letters right click on...
Is it only happening in office ?
If so try a repair install of office
try saving a txt file in wordpad to see if its only a office issue
If it s happening with all your apps when saving files.
Then it Could be the delayed write feature being very delayed due to hdd errors or the system...
It Could be related to Onedrive if you are using it?
And is locking the files while it syncs them.
Goto settings > default save locations (type or paste in Find a setting)
also check your Onedrive sync settings.