saidts wrote:
After perform a Clean Install of OS X El Capitan this problem disappear.
I started to have it since clean installed El Capitan.
Had this problem sometimes in the past with Yosemite, it was gone since a while.
The problem seems to be related with Thunderbolt, but here is a weird thing:
I have 2 WD external drives with their own power adapter, and one bus powered. The three drives are all chained via Firewire 800 and attached to a Thunderbolt display. The Macbook pro is attached via Thunderbolt to the Thunderbolt Display.
I'm having the weird ejections on the two drives NOT bus powered. The third one, which is also the last one in the FW chain, doesn't get ejected.
Here's another strange thing: I'm using these three drives as a JBOD, no softRAID, and I'e made different partitions on them. Some are also FileVault encrypted.
Some volumes don't get improperly ejected, and I get a message in finder on wake-up for those saying something like "Drive WD-xxx couldn't be powered off because it's still in use".