Uploading video which seems to keep erasing

A friend of a friend is trying to upload a video onto her computer but it keeps disappearing- like the computer erases it. My friend wants to know what to recommend- if there is a free program such as Dropbox which she can load her video directly into. Sorry if this question is not clear. I was trying to get more details but these are all available.

Your information is unclear.

FWIW, the term “upload” generally means copying a file from your computer to someplace else. OTOH, to “download” means to copy a file from someplace to your computer.

So is your friend attempting to download the video to their computer? Or are they attempting to upload the video from their computer to another location?

Is the video a file created by your friend, or someone else?
What is the video format?
What is the O/S of the friend’s computer?