Run fsck to make sure your disk isn't corrupted or damaged. Afterward,
your lost+found might get populated with the stuff that occupies the
space, done so in order for you to review.

On Sun, 14 Mar 2021 20:10:03 -0700
Marc Shapiro via Dng <dng@???> wrote:

> I had some large files (over 200GB in total size) that I no longer
> needed.  So I removed them.  They no longer show up in the
> directory. However, df, still shows the space as being used.  I
> understand that if processes are still using the files they will not
> be removed until the processes either release them, or are shut down
> (or killed).  I have tried using 'lsof -a -L1 MOUNTPOINT' to list the
> open, but deleted files.  It returns no files at all.
>
> These files are on a removable drive.  I can unmount the partition
> and disconnect the drive, then reconnect the drive and remount the
> partition, but the space still shows as being used. If the files are
> still open, shouldn't 'umount' give an error?
>
> I would rather not have to shut down the system.  Is there some other
> way to determine what is keeping these files open, or otherwise
> preventing the space from being reclaimed?
>
> Marc
>
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