BUG:Cannot change preference allow multimedia operations

1.Open Adobe Reader DC(Version 2020.006.20034)
2.Open Preference
3.Select Multimedia Trust(legacy)
4.Uncheck Allow multimedia operations
5.Close Preference(OK Clicked)
6.Close Adobe Reader DC
7.Open Adobe Reader DC
8.Open Preference
9.Select Multimedia Trust(legacy)
10.Cannot change Allow multimedia operations

How can it be changed?
(OS:Windows 10)