When I compensate for the differences in the storage devices by converting the last write date/time results to concatenated strings containing Year, Month, Day, Hour, and Second, the comparison works properly. With this approach I'm assuming that going to the second is accurate enough. You may want to use the same approach with yours. Thanks for the explanation. Here is my code:
Dim SourceWriteTime As DateTime = CDate(File.GetLastWriteTimeUtc(SourceFileName))
With SourceWriteTime
Test1 = .Year & "/" & .Month & "/" & .Day & "/" & .Hour & "/" & .Minute & "/" & .Second
End With
Dim BackupWriteTime As DateTime = CDate(File.GetLastWriteTimeUtc(BackupFileName))
With BackupWriteTime
Test2 = .Year & "/" & .Month & "/" & .Day & "/" & .Hour & "/" & .Minute & "/" & .Second
End With
Dim SourceHasLaterDate As Int16 = Test1.CompareTo(Test2)
If the SourceHasLaterDate > zero, I backup the file.
