I did a quick double check so I wonder if you meant your emails. Also, Yahoo has been known to lose emails. That's been in the news for decades.
If you can't lose things, be sure to back them up.
I just log on to my Yahoo mail and found that all my stored files are missing. Does any one know if there is a way to find these files and restore them to my mail.
I have a Lenovo H535 desktop, running W7.