I have a late 2012 iMac with a 1TB Fusion drive running Mountain Lion 10.8.5, and two external Western Digital backup drives. My Time Machine drive is a 2TB WD MyBook Studio (P/N WDBCPZ0020HAL-01) and the drive I use with Carbon Copy Cloner is a 2TB WD My Passport Ultra (P/N WDBMWV0020BBK-01). I never used the WD backup software on either drive, and I deleted that software from the MyBook Studio at some point after I started using it. Before use, I reformatted the My Passport Ultra, (all partitions) with a single pass zero overwrite in Disk Utility. In Mountain Lion both drives work without any issues. In fact, I can boot off the cloned image on the My Passport Ultra.
I was planning on updating to Mavericks 10.9.3 this week when I ran across a series of threads in the Apple Support forum and other Mac forums relating multiple instances of Mavericks updates resulting in data loss and even incapcitation of Western Digital drives, including 2TB Mybook Studio drives.
My question is: Is there any firmware update for either drive that would allow me to update to Mavericks without incident?
I realize that all external drives need to be disconnected during the Mavericks update, and the Time Machine drive should be deselected within Time Machine, but according to the reports I read, some drive failures occurred despite all precautions being taken. Both drives are dedicated back up drives, so I have triple data redundancy and I don’t have to worry about data loss from a firmware update.