Look at the lsof command (list open files) — it can tell you which processes are holding what open. Sometimes it’s tricky but often something as simple as sudo lsof | grep (your device name here) could do it for you.
You might try a lazy unmount: umount -l
Try this: umount -f <absolute pathname to the mount point> Example: umount -f /Users/plummie/Documents/stanford If that doesn’t work, try the same command as root: sudo umount -f …
YES!! There is a way to detach a busy device immediately – even if it is busy and cannot be unmounted forcefully. You may cleanup all later: umount -l /PATH/OF/BUSY-DEVICE umount -f /PATH/OF/BUSY-NFS (NETWORK-FILE-SYSTEM) NOTE/CAUTION These commands can disrupt a running process, cause data loss OR corrupt open files. Programs accessing target DEVICE/NFS files may … Read more