Hi, just wanted to transfer some files today and noticed my three year old WD MyBook 3.0, connected with USB 3.0 to my Mac Mini, is extremely slow. Blackmagic Disk Speed Test says it's just over 2 MB read / write. My first thought, of course, was that the disk is malfunctioning. But after restarting my Mac, it was back up at 90 MB/s read / write. Just a few minutes later, it's at 2 MB/s again. Why could this be? I hope the HDD isn't defect since I don't have a backup yet - I planned to get a MyBook Thunderbolt Duo 8TB next month for that reason ... Thank you for any help!