Thank you so much. This has worked for me also. Its been 5 days now and I have not had one ejection notification... VERY happy! 🙂
I didn't have anything in my "Entensions" folder and I didn't even have a "Compositions" folder, but followed the remainder of the instructions below!
"Start your Mac with safe boot into the safe mode (press and hold shift while pressing the on-button, hold it until a status bar appears under the apple). Try to reproduce the problem. If the problem doesn't occur in the safe mode, it's maybe a problem with the launch agents and the launch daemons (they are deactivated in safe mode) and the following will probably help you: Restart your Mac in the normal mode. In the finder, go to your HD > library > caches. Delete everthing in this folder (not the folder itself), do the same with extensions and compositions. Still in the library, re-name the folder "LaunchAgents" to "LaunchAgents.old", re-name "LaunchDaemons" to "LaunchDaemons.old". Re-start your mac, empty your paperbin and once again try to reproduce the problem. For me, it worked perfect: After this, I didn't had any problems, neither with ejected external discs nor with crashing. I even activated the sleep mode for the external hard disks and tried that one - no more problem. So I hope, the problem could definitly be solved and that it may help some of you as well."