So my mother asked me to download a video online, which I did. It was a youtube video which I download using other application. I've used the application for a long time and quite trust it despite sometimes its not reliable. Anyway when downloading I was not paying attention and apparently my Portable wi-fi was losing its battery and the internet got cut-off. Naturally the download failed, but I didn't know that. My mother told me the video cannot be played when she play it, so I checked and find out that the download got cancelled. And then I tried to delete the failed downloaded video but...The phone hangs!!! I didn't think anything of it at first and I innocently press Home button and see if I can delete it again. Only to find out the whole videos is the video folder disappeared. I didn't download the video again in fear it will somehow mess with the data inside the android. I have no idea what causes this nor how to fix it. My mother is distraught that her videos disappeared suddenly, this never happens before. Any help? tnx for any answers in advance.