The program certainly does work in Windows 8. However I think it might be due to the file being in System32... C:\Drivers>dir vcredist_x64.exe Volume in drive C is Windows Volume Serial Number is 0490-8AE9 Directory of C:\Drivers 08/29/2012 11:07 AM 2,373,640 vcredist_x64.exe 1 File(s) 2,373,640 bytes 0 Dir(s) 290,716,385,280 bytes free C:\Drivers>GetFileExtents c:\drivers\vcredist_x64.exe File offset 0 LBA: 31c550 Sectors: 1220 C:\Drivers>copy c:\windows\system32\netcfg-86477109.txt c:\drivers\ 1 file(s) copied. C:\Drivers>GetFileExtents c:\drivers\netcfg-86477109.txt C:\Drivers>GetFileExtents c:\windows\sysnative\netcfg-86477109.txt C:\Drivers> The original failure is something I've encountered on a 64bit OS, where if you specify "system32" Windows can't actually find that path, even though it actually exists. So if I use "sysnative" instead, the file can be found. In the above code you can see that it is able to get some data from the vcredist file, but it returns nothing from the text file, regardless if checking the original location or after a file copy.