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.
It looks like you are having trouble with Advanced Format.
The WD5000BPT uses advanced format, while your current drive, WD5000BEVT, does not. Advanced format simply means that the sector size of these newer drives are now 4k bits instead of 512 bits. This allows drive manufacturers to build larger, cheaper drives. More info.
Western Digital has an alignment tool that can be found here. It may help your issue.