A folder named for an external disk can still exist when the intended filesystem is not mounted there. A program may then write into the underlying local directory. Before a large export, confirm which filesystem currently serves the actual destination path.

Inspect the path rather than its name

Use findmnt --target followed by the quoted destination directory. The command reports the filesystem containing that location. Read its source and mount target, and compare them with the storage device or network share you intended to use.

The --target option searches the path's parents when the supplied directory is not itself a mountpoint. This is useful: if a planned external destination instead resolves to the root filesystem, you have evidence that the path is not currently reaching the expected storage.

For a directory that should itself be the mountpoint, use findmnt --mountpoint with that exact quoted directory as a separate check. A missing result needs investigation; it should not be treated as permission to create replacement folders and continue copying.

Match the source to the intended storage

Confirm the identity with the person who configured the mount, using the expected filesystem label, UUID, device or share details. Device names and familiar-looking folder labels alone can be ambiguous. Preserve the inspection result privately if it includes internal server names.

After the intended filesystem is available, repeat the check and perform a small harmless export. Locate and reopen that file from the mounted storage using the normal workflow. Only then proceed with the large job.

If earlier exports were written while the mount was absent, ask an administrator to inspect the underlying directory safely. Mounting another filesystem over it can hide those local files from the usual view; blindly deleting the visible folder is not a reliable cleanup.

The completion record should name the verified destination and show that the test export reached it. This provides evidence that a successful write did not quietly fill the computer's internal filesystem instead.

Sources: Ubuntu documentation.