Removing the troubled content can fix this permanently. My fix: Summarized: The ejection issue can be caused by corrupted or legacy file content on that Volume. My experience: I had a Volume which constantly could not be ejected properly (as in the OP's screenshots), and always needed a 'force eject', sometimes even a forceful physical disconnection (nor recommended! could damage your filesystem(s) on that disk) or a system shutdown to bypass that brute method. It runs with super user permissions ( sudo), so it sees all read/write access of all mounted file systems, and presents them in a very clear overview. There is a GUI alternative to the CLI app lsof:įseventer is a great file system access monitoring utility for various purposes. With brew cask install fseventer it may still be available on elder macOS versions. NOTE: fseventer works until OS X 10.10 Yosemite and the developer's page meanwhile got offline. ( Hat tip to Alec Jacobson's post for extra details.) It'll take longer, but it should pick up anything that's causing the disk to be un-ejectable. That will do a top down scan of the disk. If that happens, try adding the +D argument (i.e. It can also hang, but you should give it at least a few minutes before you decide that's what happened.Īlso, sometimes the base command sudo lsof /Volumes/myDrive won't find anything. One final note, lsof can take a minute or two. You should be able to eject the disk once the process/application has been killed. Here's a series of escalating aggressiveness (using the example PID of 2158): kill 2158 Note that sometimes that doesn't work and a more aggressive form of kill must be used. From the above example, it would be: kill 2158 To do that, use the PID from the second column as the ID to kill. If you can't close the application manually, you can use the kill command to terminate it from the command line. For example, QuickLook doesn't show up as an application you can get to in the Dock. Closing the application directly is the best way to fix the issue.

In this case, it's the QuickLook application that has a file open. Mds 89 root 23r DIR 52,3 432 2 /Volumes/Photosįinder 681 alans 14r DIR 52,3 432 2 /Volumes/Photos Mds 89 root 19r DIR 52,3 432 2 /Volumes/Photos The output will look something like this: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME It can take a couple minutes to run, but once it's complete, it gives you a list of open files on the disk. The fastest and easiest way would be this :- sudo lsof /Volumes/myDrive

Os x error could not unmount disk