Hi there The problem is very old, Im so tired of this stuff ) please help I have a 2.5" WD Black HDD, connected to my late 2013 13" Macbook Pro (OS El Capitan 10.11.6) via USB 3.0 Enclosure. Also another WD 2 and 3 TB Ext HDD. The problem is - when I do not use ext drive - it freezes after a 5-6 min or so... Cant even open finder, or disconnect it from MAC OS. But when I use file from it (for example mp3) everything is just fine. So, I used several disks and several enclosures. Same problem. Maybe my laptop have in some way lack of power for the USB HDD? Is there any thunderbolt case enclosures for 2.5 HDD maybe?