Outlook's default behavior is to sort new messages to the top of mailbox windows. I prefer new messages at the bottom, but have noticed that when I start reading mail, threads with new messages appear at the top. So I tried reading mail the way Outlook wants me to, but it still sorted newer messages within each thread ("Conversation") to the bottom of the group, and deleting messages still moved down (to an earlier message in this arrangement). Since it doesn't work right either way, I might as well do it the way I'm used to: newest at bottom (as of the time I first display or last Refresh the mailbox; the newest stuff still floats to the top, which I cannot prevent).

Sometimes when I delete messages, Outlook selects the next message down (which is correct, given that I view messages in ascending date order). Other times it selects the top message in the mailbox, which is only the right thing to do if it's the last message in the mailbox. This inconsistent behavior may be connected to whether any off-screen messages are selected, but that shouldn't matter. I shouldn't have to wonder where the selection will go, or try not to select messages across more than one screenful at a time, or rush through selecting and deleting mail or collapsing threads, for fear of a new message coming in, removing my selection, and selecting, previewing, and (almost) marking one of those messages read, before I had a chance to delete, mark, or collapse it. This means that if client-side filters are active, the user must wait after launching Outlook, until it's finished filing messages into the current mailbox, as new messages will constantly disrupt the selection until Outlook is finished running client-side filters. Even if Outlook has been running a while, it's easy to select a few messages for processing, be interrupted by new mail, deal with whatever was previewed and start selecting again, be interrupted again, and have to deal with the second undesired selection/preview before attempting to return to manual selection for managing email. Amazingly frustrating, and a great way to "lose" unread mail.

With a multi-monitor setup, the best way to use Outlook is with the mailbox filling one display and the attached preview pane covering most of another display. Unfortunately, as I select different mailboxes, the preview turns off. Each mailbox has its own preview state, which is important because I generally only read messages (via preview) in my "fresh" search pseudo-mailbox. In other mailboxes, clicking a messages shouldn't mark it read, so preview is a bad thing everywhere except in "fresh" (and often in "fresh", as well!); unfortunately, viewing messages in their own windows is prohibitively slow. The very confusing thing is that sometimes Outlook spontaneously turns off the preview and shrinks the mailbox to its size excluding the preview. This leaves the mailbox covering one display but not extending onto the next; it looks maximized, but isn't actually in the maximized state. When I switch back a mailbox with preview on ("fresh"), it reappears one character wide, rather than covering most of the secondary display as before. Very aggravating -- I think the workaround will be that I must use one window for my "fresh" filter (with preview), and another for other mailboxes (no preview). Hopefully I can escape more bites from these two bugs.

In Outlook, it's impossible to mark a message (un-)read from the message window, or even to determine directly what mailbox it's in. I find myself searching across all mailboxes by title and refining by date (which I can see in the message window) to find out it message is, so I can mark it unread for later attention. It's also impossible to open a message in a new window from the reading pane; the workaround is to Shift-Tab back into the mailbox window and then hit Enter to open a new message window from there.

I often want to delete a collapsed thread ("Conversation"). Outlook insists on expanding it first, which wastes time and often results in unread messages appearing and then being deleted -- disconcerting, as it gives the impression I'm losing important (unread) mail. Worse, Outlook cannot mark a thread unread without expanding it, which moves the selection into the thread and marks that one or two messages read when deselected (unless the selection lasts a second or less, as I have set Outlook to mark messages read after a second, because I cannot eliminate the delay, and above one second it doesn't automatically mark short messages which I read quickly as read; I have to go back and mark them read manually later). If I have just read a new message in threaded mode, and want to mark it unread, I have to either hit Control-Q to mark it read or move to another message and back (assuming I've had the current message previewed for at least a second), mark it unread (Control-U), then hit left-arrow to collapse the thread.

Worse is when I want to mark a whole thread unread (more common). Then I have to collapse the thread to implicitly select the whole thing (switching to and from the mouse slows me down, and I get too much mail to be inefficient in dealing with it); hit Control-U to mark the whole thread read (implicitly expanding it), then hit left-arrow within a second to collapse it again before Outlook decides I've read a message in preview.

When I delete a message, Outlook immediately selects (and previews, in "fresh") another message. When I'm reading mail, this is generally what I want, so I can deal with the next message. When I'm trying to delete or file mail, it means Outlook automatically starts the process of dealing with another next message, and unless I'm very quick marks it pseudo-read (as soon as I deselect), so I must decide what to do about the new selection. This makes it harder to stop reading mail in the current mailbox, as every time I complete an action, Outlook picks the "next" message and engages me in dealing with it; stopping without losing unread status on a message I haven't actually read yet requires contortions. When I know I'm about to stop, I tend to deal with a message or thread and then hit Control-up-arrow to jump to the top of the mailbox, which should be the first message I read (so already marked read), but is often a new message that's come in recently; I then have to decide on and handle that before I can move on to another mailbox or activity.

Normally, when a thread ("Conversation") is collapsed, Outlook deselects its messages. Sometimes (unpredictably) it still shows the preview for a hidden message, which breaks the Control-Q Control-U left-arrow dance, and I have to instead hit Control-Q Control-U left-arrow up-arrow to get a collapsed unread thread.

F5 (Refresh) doesn't clear collapsed conversations; this is annoying. On the other hand, sometimes messages disappear immediately upon being marked read, which means I don't even get a chance to mark them unread; they're effectively just gone. I have no idea what triggers the second problem; fortunately it's rare, as it tends to result in losing mail -- often mail I was saving for later attention.

Control-Q marks individual messages read, but cannot be used on whole mailboxes (with the selection in the left-side mailbox column). There's no good reason for this, as marking whole mailboxes read is a common function, and in the pop-up menu, it just doesn't have the obvious keyboard shortcut.

Outlook cannot select multiple mailboxes at one time, which is ungood; on the other hand, it makes an effort to be helpful -- when I select a mailbox, it kinda-sorta move the selection into the message list (which is pretty reliably what the user really wants, since you can't do much with mailboxes except delete or move them). It's all a bit confusing.

If I have a message which has been previewed for over a second, I know it's effectively read (it will be marked as such as soon as I deselect it, unless I drag it into another mailbox first). It would be good if I could use Control-U to tell Outlook not to mark this message read as soon as it gets deselected, but instead I have to mark it read, then mark it unread, and then move away within a second -- before the preview timer marks it mostly-read again.