Check your View settings and change it to All Messages, not just unread ones
or those younger than XX number of days. You should not use your Inbox for
storage. Make a subfolder of the Inbox to save items.

"hms" wrote:

Messages in my inbox after a few days may disappear, they can be found by a
search, which says they are in my inbox, i can move them to any other
subdirectory, but not back to my inbox where i want them.