Hi Thomas,
If the DateTimePickerAdv is bound to a DataSource that may contain null values in the date field, when you add the binding you bind to "BindableValue" and not "Value" as shown below.
this.dateTimePickerAdv1.DataBindings.Add(new System.Windows.Forms.Binding("BindableValue", this.dataSet11, "Table1.Date"));
Please take a look at the sample in the following KB Article.
How can you setup databinding to your DateTimePickerAdv ?
Thanks for choosing Syncfusion products.
Regards,
Anu.