I have a 2018 MacBook Pro touch bar running Mohave (10.14.5) and USB-C Mini docking station. I have an external SSD in an enclosure connected to one of the rear USB-C connections on the rear of the dock.
When the MBP goes into screen saver I come back to multiple notifications of the disc being ‘Not disconnected properly’. Sometimes in excess of 30 notifications in an hour. When I open the MBP back up the SSD is connected fine but cancelling 30 notifications every time you go to work on your computer is painful!
Anyone else seeing this? The SSD is fine when connected directly.
Thank you so much for reaching out to us, I am sorry to hear that you are seeing this strange behavior, but I would be happy to clarify what is causing this issue.
Recently (in the release of Sierra) there has been an apparent issue with utilizing external HDDs/SSDs via USB hubs when connected to Macbook Pro, Macbook Air, and macOS based systems. We have reached out to Apple a number of times, and submitted multiple bug reports, but we have not received any information back. The problem does not specifically relate to just our products, and is effecting other hub manufacturers as well. The only two solutions provided are to directly connect the drive to your system, or see if adjusting the “spin down hard disks” option is not selected inside of System Preferences > Energy Saver.
There are multiple threads on Apple support forums from many different people running into the same solution, and if you would prefer, we would be more than happy to send various links on this forum post.
I hope this information helps, please let me know if you have any additional questions or concerns, and I would be more than happy to assist.