Hi, I'm experiencing an odd issue where an external hard drive is slowing down the both the internal hard drive and other external hard drives on my iMac. Hoping someone here has some insight that can help me out. Here's the details: I'm running a 27" late-2012 iMac (32GB RAM, 3.4GHz i7, 3TB Fusion drive; I/O Thunderbolt 1, USB 3.0). The drive that's causing the slow-down is a 10 TB LaCie d2 Thunderbolt 3/USB-C external hard drive (model STFY10000400). I also have two daisy-chained 6TB LaCie d2 Thunderbolt 1 drives connected via a Thunderbolt port and an older LaCie Rugged drive connected via a FireWire-800-to-Thunderbolt adapter. Connected to the other USB 3.0 ports are a Apple wired keyboard, an Apple SuperDrive (DVD) and my iPhone 6 charger. Here's the problem: When the new LaCie d2 Thunderbolt 3 external hard drive is connected (via LaCie's USB 3.1/type-C to type-A cable), the response time on all the other drives—both the external drives and the internal iMac Fusion drive—slows down. If I move or delete a final on any of the other drives, it takes 4 seconds for the file to move to the trash or other folder location. If I unmount the Thunderbolt 3 drive, the responsiveness of all the other drives goes back to normal. I move/edit/delete/copy/paste hundreds of files a day, so a 4 second delay adds up quick and puts a real kink in my work process. I'm hoping someone might have some insight on what's causing the problem and how I might address it. Thanks!