Most of time, Disk Utility doesn't even read the drive. Similar to what happened above, when WD My Passport is uninitialized on Mac, Disk Utility may show the drive uninitialized and all partitions get lost. It allowed me to run first aid, but then it just said 'operation successful' and there's no change to the drive. Disk Utility displayed the drive as uninitialized. I've replaced the cable (no difference) and also run the Disk Utility on it.
A few days ago while I was trying to transfer files from the WD My Passport Ultra 2TB to the Time Capsule, it suddenly became unrecognizable.
