Don't know if this will help, but worth a try:
Remove any DVDs from the drive
Open Settings/System
Click Default Apps
Check What it says for "Video Player) (It's probably just got a plus sign)
Click Choose Default
Select the app you want to use (I chose VLC media player, but obviously that will only be in the list if it's installed on your machine)
Close Settings
Insert the DVD
I've just tried playing a dvd in one of my W10 machines. First attempt was an utter failure because it's a blu ray disc and my drive isn't.
The second one played fine through vlc.
When I put the disc in a small pop up appeared - tap to choose what you want to do with these files (or something like that). I closed that box and openedn VLS and clicked the 'play' button and off it went, through the trailers and in to the film.
Now, I am sure I ticked a box in the Windows 10 settings to stop Windows trying to find an App automatically. If I remember how I did it, I'll let you know