Hi Jason,
I’m sorry to hear that didn’t seem to help.
It’s really interesting that the other USB hub didn’t have the same problem. I wonder if this other product uses a different chipset for its USB hub. Could you please provide its model number or a link to it online so we can review its specifications? Also, is the USB hub that is working properly connected through the dock or directly connected to the Mac?
This “Disk Not Ejected Properly” issue can be caused by many variables, and as alluded to before it’s reported in several places online even when not using the TBT3-UDV. This leads me to believe that there may still be some other potential factors we could change in hopes of alleviating this behaviour.
To clarify another point, is your MacBook Pro the 15" model or the 13" model? If it’s the 15" model it may be worth trying to connect the dock to one of the Thunderbolt ports on the other side of your Mac to see if it behaves differently. The two sides of the Mac use separate Thunderbolt controllers so this could be a useful step to try.
Another possible workaround for this problem that my colleague Josh mentioned in another thread in our forum is to try Ejectify, a third party application that automatically unmounts and remounts external drives when the Mac is in different system stats such as when the displays turn off and on or when the system sleeps. Note that we haven’t tested this app, but this may be a good way to at least avoid the drives from ejecting unsafely when your Mac sleeps.
Here’s a link to Ejectify if you’d like to try it: https://ejectify.app
Please let me know if you have any questions as well. My apologies again for the frustration.
Sam
Plugable Technologies