I'm getting this error also, how do you disable MimeTypeChecking in a MVC app? I need this to support .AI files.
This does not work:
public override UploaderValidateOption GetValidateOption()
{
var option = new UploaderValidateOption
{
MaxSizeKB = Settings.Instance.MaxSizeKb,
EnableMimetypeChecking = false
};
return option;
}