When i want use ??/08/2015 in my date field. Its nothing can show, why? Maybe it just happen in windows 10?

I suspect the problem is that you have a different date separator after updating to Windows 10.

A date is stored as a number but when you search for it is converted to a string.

So if you switch from dd/mm/yy to dd.mm.yy it will work fine in fields etc, but when you search you have to use ??.08.2015 rather than ??/08/2015.

This can be tricky if you have used the formatting in a derivation etc.