How to Check That a File Transfer Is Complete

Compare the basic evidence

Record the source’s item count and, where available, its total size. Compare those with the destination after the transfer completes. A different size can be explained by conversion or filesystem reporting, but it deserves investigation rather than an automatic assumption of success.

Open representative files

Choose the first and last item, the largest file, and a few different formats. Play a video near its end as well as its beginning. For a document, check its page count and a page containing small text. An intact filename and thumbnail do not prove the entire content arrived.

For high-value files, a checksum comparison can provide stronger evidence when your tools support it and the transfer preserves the exact bytes. Converted copies will not have the same checksum as their sources.

Keep a simple record

Label the destination folder and note when you checked it. Do not immediately reorganize or delete the source while a partial transfer is still being reconciled. If something is missing, copy the missing items into the intended folder and repeat the check. A synchronized folder should not be your only independent backup if deletions can propagate to it.