sealed method mock calls actual method instead of mocked

[LogunovAV]

if you Mock the method of the class which has sealed identifier, the mock.Object.Method will call an actual method, not the mocked one.

[AlexRuMath]

if you Mock the method of the class which has sealed identifier, the mock.Object.Method will call an actual method, not the mocked one.
Example:

[stakx]

Moq doesn't support sealed classes/methods. You can only mock non-sealed types and virtual, non-sealed methods.