I open a email then it just disappears and i can not find it

1

I have two email address and it does not happen on the other one.

2

Do you use any rules?

3

only spam filter and it is set up the same on both email addresses but one does not disappear.

4

It is very strange. You are trying to tell me that when you doubleclick a message that it opens in new window and then it disappears?