Thanks Jerry,

After further investigation using the VB FileDateTime() function employed in the article you highlighted, I've discovered that the problem is occurring where files have no created date at all. The FindNextFile API function tends to default these to 1/1/1980, while the VB FileDateTime() function decides that these should be reported as the Modified date instead.

All very odd, but at least I've got to the bottom of it.

Thanks very much for your help.