Read mail continues to show as Unread

I had the same problem of emails not being marked "as read." After installing an update, it got better. However, the same problem is occurring. If I restart my computer, the problem disappears for a while, but it's a nuisance to have to restart so often. Another problem is with Safari. It will show that it is not connected to the internet. If I close and reopen, it works. What a nuisance both of these problems are.

Is there any known solution to this? It's a huge problem for my workflow.

I have found that the only way to resolve this as of now is to go into Mail > Preferences > View > Switch to Classic Layout. I am working on a final resolution without having to recreate the profile and will report back.

Unchecking "View by Conversation" under the View menu seemed to fix this.

Sorry, I meant "Organize by Conversation"

Why hasn't Apple done anything about this problem? It's clearly a widespread issue, given the # of responders to this thread and we all have the same problem.

C'mon Apple.

The only method I have found to reliably workaround this issue is to move the emails that I have read that are still being flagged as Unread to the Trash, then from the trash back to my inbox.