Good emails sometimes are put in the SPAM folder. To find them we need to be able to SEARCH the SPAM folder.
William Loob commented
Same here. I always have a few legitimate messages ending up in the spam folder, so I check through every few days to restore those. Now a new glitch: When I click on the spam folder, I only get a list of a dozen or so recent messages and the rest of the screen is blank. Even though moving the mouse over "Spam" shows there are hundreds in there from the past week or so. I can't look through the list to find any legit messages that might have gotten sucked in there.