I've been using Outlook heavily for a while now, so I have found many flaws. I realize Outlook 2007 fixes some of these, and includes its own issues. Note that I have complained about most of these here -- this post is a consolidation & update.

Filtering

• Outlook Options (program-wide preferences) is not available from message windows -- only from the mailbox viewer window. This is true in Thunderbird/Mac too; presumably copied from the MS model. Dumb.
• Outlook's filtering isn't very good. It is not flexible enough -- no booleans & very limited criteria available.
• Two filters that match the same message will typically "copies" the message to two different different mailboxes. This is confusing -- why does the first match move (from Inbox) while the second copies? There is a "stop filtering" action, but turning it on for each message is a waste of time and precious filter ruleset bits.
• I hit the accursed 32kb rules limit. Despite this post, I am capped at 32kb total in rules (client-side + server-side). Apparently this limit is raised to 256kb if the client is Outlook 2007 and the server is Exchange 2007. Someday, perhaps.
• Some filter actions are handled on the server, while others (particularly flagging) are only performed on the client. This complicates rules unnecessarily, and creates inconsistencies if the PC is shut down or logged out. PCs need to reboot relatively frequently for patching and updates.
• I thought it was cool that Outlook checks group memberships automatically when filtering. Unfortunately this cannot be turned off, so it's quite awkward to filter messages sent to a list separately from messages sent to a member of the list.
• The pop-up window for new mail appears before filters run, so I am notified of new mail. I don't want to see.
• If I click on such a notification, Outlook shows me the message, marks it as read, and then filters it.
• I have several filters that match on Subject strings, but Outlook only offers "contains" (no "starts with" or "does not start with"), so I cannot specify original messages, and distinguish from replies/forwards.
• The filter area shows a list of criteria with checkmarks at the top with blue underlines under the keywords. The bottom shows the same labels, with the same blue underlines. But at the bottom they're "links" to dialog boxes for entering the criteria, while at the top the same "links" aren't clickable. Way to misuse a visual cue, and do it in the most confusingly inconsistent way possible!
• Oh, and the rules dialogs are all modal, so once I start creating a rule, I cannot open candidate messages for comparison against the rule.

Display & Windowing

• I find the Reading pane indispensable, because Outlook is slow to load messages into new windows.
• Inbox does not appear at the top of the mailbox list!
• Outlook keeps forgetting my favorite mailboxes.
• When I relaunch (or launch on another PC), Outlook loses my view settings.
• Outlook does not remember open messages (including drafts) across launches. In fairness, Eudora is the only client I know that does this -- apparently Notes does too.
• I can make Outlook sort a mailbox with the newest messages at the bottom (the default is newest-at-top), but then when I click the mailbox, Outlook selects the bottom (newest) message in a mailbox, whereas I want to read oldest first.
• Outlook can allow commas as address delimiters (which is what they are in the actual mail messages, as part of the SMTP standard), but then I cannot type names, because we have autocomplete disabled and Outlook doesn't recognize a correct "Last, First" recipient when it's set to allow commas as delimiters (even though Outlook uses them once I click Check Names).
• I tried to keep my mailbox "caught up" or "clean" (all messages read). Outlook doesn't mark a message read until I deselect it. This meant that when done, to have it stop showing that last message as unread, I had to select something else.
• When reading a bunch of new messages, and Outlook selected one I didn't want to read, I had to click another message to get the Mark Unread contextual menu command; then scroll up to the top and click on the first message to continue.
• Now, after a few problems where Outlook marked a message read before I was ready, I have it set to never mark messages read when I read them in the Reading pane. As a result, I spend more time than I really want manually marking messages read, but overall it works better this way.
• I can collapse a thread to easily mark the whole thing as read, but then I have to expand it again before Refresh will hide it from my fresh search mailbox.
• Refresh (F5) doesn't work. I have refreshed as many as 10 times without having the list of messages become correct.
• When I delete multiple messages and some are out of view, Outlook seems to select the top message in the current window. The "next message" does not depend on where the scroll thumb is! Ironically, iTunes/Mac has a similar bug.
• In Conversation view (which would be a lot more useful if it didn't waste 2 messages worth of space per "Conversation"), if I use down-arrow to select the next conversation, it expands the conversation instead. Use left-arrow/right-arrow to collapse/expand conversations -- they aren't needed for mailbox navigation! At least Control-KP+ expands all conversations.
• I cannot find a good way to sort threads by date; I'd like every thread (perhaps every thread with new messages) grouped together, with the messages in each thread sorted internally by date, and the threads sorted by date (typically of the first message). In Outlook I can group "Conversations" by Subject: or group by From: line, but new messages/threads keep showing up at the top of the mailbox. This makes it very difficult to work through recent mail in chronological order, as not only do new things keep popping up at the top of the list, but additionally existing threads move up when someone replies to them. I find myself constantly working down from the top, towards some unmarked line which divides "stuff I've at least initially processed" from "earlier stuff I haven't yet seen" (much of which has to be deleted); when I finish scaning the second group, the invisible line divides "stuff I've at least initially processed" from "older stuff I've at least initially processed, which definitely needs attention at some point". Not a good way to work, but the best I've been able to manage in Outlook so far.
• I have figured out more what's wrong with Refresh. First, I have to hit F5 repeatedly to make Outlook clear more and more read messages from unread-only views; second, collapsed conversations are not cleared; I have to expand them out and then hit F5 again. This is particularly annoying because Outlook has such a strong tendency to always keep one message selected and thus read (although it's not marked read, so I cannot simply mark it unread; I have to mark it read, then mark it unread, and then make sure Outlook doesn't preview it again), so it's quite difficult to reorganize a mailbox and get to a "clean" view (only new messages/threads) without losing some messages which Outlook insisted on selecting/previewing/marking read while rearranging.
• 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 switches off. Each mailbox remembers its own preview arrangement, which is important because I generally only read messages (via preview) in my "fresh" search pseudo-mailbox. In other mailboxes, clicking a message shouldn't mark it read, so preview (the "Reader pane") is a bad thing everywhere except in "fresh" (and often in "fresh", as well!). Aggravating matters, sometimes (mostly when I lock the PC) Outlook turns off the preview and shrinks the mailbox to subtract the preview area. This leaves the mailbox covering one display but not extending onto the next. When I switch back to a mailbox with preview on ("fresh"), the preview reappears one character wide, rather than covering most of the secondary display as before. Very aggravating -- I now use one window for "fresh" and one for other mailboxes, and gave up on windows larger than one display.
• 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 (using LookOut) and refining by date (which I can see in the message window) to find the containing mailbox, and then doing another search within that mailbox list window (which is slow), so I can select the right message and mark it unread for later attention -- fortunately I don't have to do this very often! 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 the message window from there. Dumb.
• 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 had 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 had to go back and mark them read manually later). If I had just read a new message in threaded mode, and wanted to mark it unread, I had 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 was marking a whole thread unread (more common) from the keyboard. Then I had to collapse the thread to implicitly select the whole thing, hit Control-U to mark the whole thread read (implicitly expanding it), and then hit left-arrow within a second to collapse it again before Outlook decides I've read a message in preview. Now that I mark everything read manually, I still need 4 keystrokes, but at least the last one isn't racing the clock.
• When I delete a message, Outlook immediately selects (and in "fresh" previews) 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 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 not that common, as it tends to result in losing mail -- often mail I was saving for later attention.
• 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.
• 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.
• The flag column is at the right side of mailbox list windows, and cannot be moved. I'd like to move it left, to be alongside the other important columns, but cannot.
• In general, there are many customization options for mailbox display, but the controls are all over the place, so hard to find and confusing to use.

Things I like

• Outlook can show me mailing list (group) membership. It's called "Outlook Properties" in the menu, despite being maintained on the Exchange side, but after I got over thinking that couldn't be the right place, this is quite handy.
• The setting to view all received email as plain text is amazingly useful; there's a handy option at the top of each message window to see formatting.

Searching

• There are at least 4 different types of Find. Control-F in some places, F3 in others, F4 in others, and LookOut (now Live Search). Sometimes I hit Control-F to Find, and Outlook forwards a copy of the message instead.
• I cannot Find unless the selection is in the right part of the message window. Amazing!

Super-Modal

• I have to use View Options to see full headers (in the Message Options window), but while that window is open, the main Outlook program is visible but completely unresponsive. Alt-Tab doesn't show Outlook windows, and I cannot access the others until I close. I thought Outlook had crashed, until I realized it was accessible again after I dismissed Message Options.
• Similarly, emptying Deleted Items (which must happen every time I quit) locks up the whole program until done. In fairness, other programs empty the trash modally, but don't necessarily force it at quit.
• Every single time I Logout, Windows tells Outlook to quit. Outlook starts emptying my Deleted Items mailbox, and I watch the race. Then I normally cancel the logout so Outlook can finish -- it's almost never fast enough to complete the operation before the Windows timer runs out. This means automated reboots, as for patching, are crashing Outlook while it's in the middle of modifying my mailbox on a regular basis. I guess this doesn't cause huge amounts of grief because everything in Deleted Items is expendable, but lame lame lame.

Keyboard

• I found a couple pages of Outlook keyboard shortcuts (the online help lists shortcuts too). Many are standard Windows shortcuts, but a few were new and useful for me.
  • http://www.hongkiat.com/blog/80-keyboard-shortcuts-for-microsoft-outlook/
  • http://www.rnib.org.uk/xpedio/groups/public/documents/PublicWebsite/public_rnib003594.hcsp
• Now that I use Thunderbird at home and Outlook at work, it strikes me how similar Thunderbird is, even extending to some misfeatures (design flaws, not quite bugs), such as over-using the Esc key. Thunderbird has a few notable improvements, such as being able to mark messages Read and Unread with the M key, instead of Ctl-Q/Ctl-U, or S to flag messages (stored as an IMAP tag; this shows up in Eudora as Label 15). Also, with a mailbox "selected" in Outlook, Ctl-Q doesn't mark all messages read, as it should.
• In both Outlook and Thunderbird, Esc closes message windows; this is inconsistent with all other full windows, which are closed with Command-W/Control-W, and makes messages feel particularly ephemeral. In Outlook, when I open a received message and hit the Space bar to scroll to the next page (which works in every other email client and browser I know), it instead inserts spaces at the beginning of the received message, which is completely absurd.

Misc

• AutoCorrect absolutely would not let me type "SAs" (System Administrators) until I killed it.

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