If you have a "good" NOT SPAM, do this:  Highlight it, right click, then point to Spamhalter classification, and select Train message as NOT SPAM.  Then while it's highlighted, go to Tools, and point down the list to Spam and content controls, then click on Global Whitelist to save the email address, so in the future those emails will be recognized as NOT SPAM. 

I receive about on hundred messages a day, of which about five aren't spam. I've set up a lot of filters (390), and until a few days ago, only one or two spams would slip through during a week. For the last several days, everything has been going to the Deleted Messages folder. If I go through the mail and move real messages to the New Mail folder and click on it, everything I've moved goes back to the Deleted Mail. If I move it to a third folder, then drag it to the New Mail folder, it stays. I've checked my filters and can find nothing that should cause this.

Would the number of filters be related?

Among the deleted are some that are marked as significant.

Does anyone  have any ideas how to fix this?

Thanks, Clark

New Mail Filtering Rules will be applied when the new mail folder is eitjer opened or closed, depending on how you have set it up. Rules that are applied to messages when the folder is opened will only apply to unread messages.

I would examine the messages and try to determine what has triggered the rule(s).

Do you use Spamhalter?

It's set up to operate on the folder when it opens. Those things that are supposed to be filtered out are filtered out. Those things that aren't supposed to be filtered out are, too. I can find no correlation between the filters and the messages that should not be filtered out but are. Searching the filters is problematic because there is no search function for the filters, or if there is, I haven't found it.

I'm using Spamhalter, but it hasn't put anything in the spam folder in a while.

That's a lot of filters... I couldn't keep that many straight.  If you're getting a hundred spam emails a day, might be time to abandon that address?  

 Also, if you know exactly who you get/want emails from you can set that in the whitelist, so that only those emails come through.  Might be easier to manage a positive instead of a negative?  Good luck, and death to spammers!!! 

A quick way to verify whether it is something in the rules that is causing the problem is to test with the rule set disabled.  To disable a rule set add an Always Exit rule as the first rule.

BTW, the new mail filtering rule set is stored as a file named WINRULES.PMC in the mailbox directory.  It is a text file so can be opened & searched with a text editor.  Best to make a working copy of it in a temp location.

Consider working towards getting Spamhalter working.  It would remove the burden of trying to maintain and troubleshoot a 390 rule filter set.