after little research iam found the issue iam using many cloned virtual disk drives which has same serial number (becase was cloned)
diff uses "stat" call to get info about disk so when i use sync between this disks i have another mont drive letter but same serial number, same path diff -urN D:\path E:\path give me there no diff, path the same so i propose little fix for this just edit at the file diffutils-3.7\lib\stat-w32.c to "buf->st_dev" after assign "VolumeSerialNumber" add disk drive letter this will produce unique "st_dev" and diff will work for such cases
