I have Windows 7 Ultimate 64 bit installed on a Western Digital 500GB drive (WD5000BEVT-22ZAT0) that was partitioned automatically by Windows as 100MB System Reserved and 465.66GB drive C. There is also an unallocated second Western Digital 500GB drive (WD5000BPVT-22HXZT1) that I want to use for RAID 1 to mirror the first drive but I get an error message stating “ALL DISKS HOLDING EXTENTS FOR A GIVEN VOLUME MUST HAVE THE SAME SECTOR SIZE, AND THE SECTOR SIZE MUST BE VALID.” I uninstalled Windows patch KB-982018 but I still get the same error message. Could you please let me know how to resolve this? Thanks.