I bought this WD Passport 4TB last month and ever since installing it on my Mac Mini it has been causing the machine to crash regularly. I cannot understand why this is recommended for Mac - it does not automatically mount when attached via USB and for Time Machine to work on it requires re-formatting of the disk. Frequently it requires specific unlocking on the device, even when you have selected the option to have it automatically recognise your machine. In these days of plug and play I had expected much more for seamless operation for the price asked.