Several months ago about 400 email messages disappeared from my system ( Windows 8.1) As this is a new computer, I returned it back to the store and the attendant clicked on Recovery and all of them returned.

Now it has happened again and I cannot recover the previous ones that disappeared, plus new ones from my in box.

I have tried some of the suggestions you have already made, with no luck.

What can I do.......many of these emails contained photos.