Ok, sorry fot all the mess I created, the long history is:
I have the source on the OP of this thread that is the code o referenced on last post.
Later you share another source which have the CINIFILE.CLS & HugeBinaryFile.cls and few extra lines on clsDrive.cls but have the same overflow on big drives. for that sources I did comment the line "drvTotalSectors = oInit.TotalSectors" on clsDrive.cls and compile it. that is the one I shared.
So I just realize you create the GitHub repository, and make corrections to code, now the released one on GitHub works fine when you have big hard drives.
The one on GitHub works great, the only thing I find is what the file CINIFILE.CLS have the end of lines as LF not CRLF so it is not open by Visual Studio 6.0:
View attachment 295523
I Think the version on GitHub should be raised to avoid conflicts.
Thanks for your great work