I have 3 users out of about 20 who are constantly complaining that they are missing emails because they are getting marked as read without their viewing them.

For two of these users, this is happening not only with their personal mail, but also when using a shared mailbox (Team mailbox from OpenNTF)

The unread mark options on the databases are set correctly. They are working on databases on the server - no replicas involved.

Everything else I could find as possible solutions to this in the forums is not applicable - e.g. preferences are set correctly etc.

I found this asked in the forums a number of times - but have not seen any answers yet.

Anyone have any ideas? Do I need to create new databases?

These DBs were created in v6 and have been upgraded as we upgraded.