Trouble with mails redirected to Junk Folder

I have an issue with some users that have a lot of internal emails rerouted to Junk folder.
They all share that recently were reformatted and installed Avast from scrath…
It seems i can’t find any solution…i have turned almost everything off but nothing…
Any ideas?

Are you sure this is not the built in message filter in Outlook catching these? Try turning off the built in spam filter for a bit to see if the messages don’t get moved there.

They don’t have any rules or anything similar.
As a test we installed the Free Version of Avast and is working correctly.
By the way does anybody knows if i can use the Free Version instead of the Paid Version…please note that i have PAID for the Avast EPSP but is getting harder by day to manage it…we are talking a lot of headache…the initials tests of the Free Version seems that it is a lot better product…(?)

The free version is NOT a better product, it is a WORSE product. The main differences here are anti-spam module, and avast! Firewall module. Remove those modules from add/remove programs for testing. Set antispam to whitelest all emails addresses replied to, and all email addresses in contacts. I have thousands of these out there, and none of my clients have any of these issues.