I have this drive (2TB MyBook) and a 1TB MyPassport that I havebeen using for Time Machine backups on an iMac fall 2009…
As the last step of a general upgrade, I installed Yosemite 10.10.4 yesteday. I reformatted the 2TB drive in the mac drive util and and started a clean backup. After a few minutes, Igot a message “Backup Failed” and one saying “Disk Not ejected properly.” The drive was not visitble in the drive utility. I’ve gone through unplugging and restarting the disk. That berings it back. I’ve verfied and repartitioned numerous times. Once a backup went one hour before failing; otherwise its lasted only a few minutes each time.
I’m using hte same cable on my 1tB drive, and that has no connection problems (except its nearly full and therefore unable to do even an incremental backup, and has Mavericks so I can’t roll back.) When the 2TB drive is visible in the drive util, it shows the backup partition and says “inProgress” calculating size.
Is Yosemite the culprit, or something else?