With the publication of the 9.1.20091.2039 service release of NetAdvantage for .NET 2009 Volume 1, we're seeing a few reports of an issue with WinDateTimeEditor when upgrading to this service release.

The issue is either a warning or an error encountered at design-time, with the following message:
"The DateTime property cannot be set to a value that is outside the range determined by the MinDate and MaxDate properties."

This issue was introduced in a previous service release, where the DateTime property could be set to null (Nothing in VB.NET).  In some cases, this would insert a line similar to the following in the Windows Forms Designer Generated Code section:

C#:
this.ultraDateTimeEditor1.DateTime = new DateTime((long) 0);

VB.NET:
Me.UltraDateTimeEditor1.DateTime = New Date(CType(0, Long))

As of this service release, this line of code should no longer be automatically inserted by the control.

The service release will not itself remove this invalid line of code, nor will the Project Upgrade Utility or Project Upgrade Add-In.  To clear the errors and warnings, manually remove this line of code from the Windows Forms Designer Generated Code section.  With the changes made in this service release, this invalid line of code should not return.

If you follow these steps and still encounter this issue, please submit a support request so that a Developer Support Engineer can assist further.  Should there be further developments with respect to this issue, I'll follow up in this thread.