Thank you for writing to Aspose Support team.
This is not an issue with Aspose.Email but can be re-produced as follows:
DateTime dt = DateTime.Parse(“1/1/0001 12:00:00 AM”);
long ltime = dt.ToFileTime();//Here is the exception
Please notice that the oldest valid date/time for Win32 FileTime structure (Microsoft defined computer data type) is 00:00:01am Jan. 01,1601 in UTC (Universal Time Coordinated).
Yes, I agree that 1601 data is the min FileTime.