Outlook 2007 is slow, RSS broken

Users are reporting that Outlook 2007 is slow – much slower than Outlook 2003, which it is meant to replace.

Experiences vary, but the worst affected are those with large mailboxes. Large in this context means thousands of messages and several GB size. Looking at the newsgroups there may be a particular problem with Outlook on 64-bit Windows. I’m not impressed; though it’s not yet clear how widespread the problem is. I’d be interested in comments.

Confession time: I have a huge mailbox. That means I can easily find old email correspondence, and that’s a feature I value. Furthermore, I lack the time or patience to sift through and delete what is no longer required. Unfortunately, the most effective advice for those suffering from slow Outlook 2007 installations seems to be: reduce the size of your mailbox.

While there may be good organizational reasons for doing this, it seems odd that it is needed on today’s machines, with vast amounts of RAM and disk space, and unspeakably fast CPUs. And if you use Exchange, be sure that you archive to a server location, otherwise you can end up with several little archives littered over every machine you use, and they likely will not be backed up.

Why should users have to prune their mailbox because the very latest Outlook cannot cope with it as well as the older version? Surely it is not that difficult to query and display emails from a local database?

I’m also disappointed that, for all the talk of user experience, the new Outlook does not slow down gracefully. You know the kind of thing: you start the application and an unresponsive, semi-painted window appears for a while. You click to change folders and the application appears to hang. You click to drop-down a menu and the application freezes for several seconds. Isn’t this the kind of thing that background threads are meant to help with?

As for RSS, I can’t make sense of what Outlook 2007’s designers were aiming at here. Note that I think the RSS central store, installed with IE7, is a great idea. However, “central store” in this context means central to the local machine. What Outlook seems to do is to copy the contents of this store to your mailbox and then keep it synchronized. I think that’s a mistake: mailboxes are big enough already, and Outlook would do better to query the central store dynamically.

The real problem comes when you use Outlook with Exchange. Many users take advantage of the server-side mailboxes in Exchange by using Outlook on several different machines, all pointing to the same Exchange mailbox. For me, this is the primary advantage of Exchange and Outlook. But what if those several different machines have different RSS feeds in their central store, or even the same ones?

So far, it appears that Outlook cannot cope. I end up with duplicate feeds, I end up with feeds showing in the RSS feeds folder that are not listed in Tools – Account Settings – RSS Feeds; in fact this list is empty on my desktop machine, Sync is turned off, but I still have a ton of feeds in the Outlook RSS feeds folder.

It seems simple to me. Either Outlook’s RSS integration should be 100% local, in which case you just see what is in the central store on your current machine. Or it should be 100% server-based, in which case Exchange should handle the RSS updates. Mixing the two is just silly.

Tip for improving Outlook performance: if you are happy to do this, go into Tools – Account settings – Microsoft Exchange Server – Change – More settings – Security, and remove the checkbox from “Encrypt data between Outlook and Exchange”. Other factors may be search engine integration (Microsoft’s or other), A/V integration, or other add-ins.

Bottom line: I suggest caution before rolling this out over a network.

Update: other tips you can try

A few other things that have helped people:

  1. Exchange users: Remove Outlook 2003 and do a clean install of Outlook 2007, making sure that a new offline store is created from scratch.
  2. Run on Vista.
  3. Turn off indexing. Tools – Options – Search options – uncheck all folders. It’s a shame to do this as the indexed search is useful.
  4. Let indexing complete. Might be worth leaving the machine running overnight.
  5. Reduce the size of your mailbox (of course).

The above will not solve all the problems, but can mitigate performance issues.

Further update

Microsoft has posted some official workarounds. See here for comment and link

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Related posts:

  1. Why Outlook 2007 is slow: Microsoft’s official answer
  2. Slow Outlook 2007: the comments keep coming
  3. The mystery of the slow Exchange 2007: when hard-coded values come back to haunt you
  4. Outlook HTML is better broken and safe, than rich and dangerous
  5. Hi, got a Dell? Outlook slow? Let me fix it

196 comments to Outlook 2007 is slow, RSS broken

  • I had similar problems. My .pst was 420 MB…checking the large mail search folder showed the fattest messages. After deleting I compacted it, and it’s down to 250 MB. Feels a bit more spry.

    It does seem to hand quite a bit tho. There’s definitely some stability issues us early adopters have to deal with.

    I also had to create a new Outlook profile, before that I couldn’t send/receive new mail.

  • Tim

    > My .pst was 420 MB

    That’s small 🙂


  • I don’t suppose we could get you to take (another?) look at Lotus Notes — tested up to 64 gigabytes per local file, with a full text index providing search results in seconds…

  • The real problem comes when you use Outlook with Exchange. Many users take advantage of the server-side mailboxes in Exchange by using Outlook on several different machines, all pointing to the same Exchange mailbox. For me, this is the primary advantage of Exchange and Outlook.

    Primary advantage compared to what? POP3 access? I’m not challenging you, I’m trying to understand what your point of reference is.

  • Tim

    Primary advantage compared to what? POP3 access?

    Compared to any mailbox that it is not server based. The Outlook/Exchange combination has all the advantages of a local store (work offline, take your mailbox with you), as well as the advantages of a server-based store, such as web-based mail access. If you regularly use more than one machine, such as a desktop and a laptop, this helps enormously.

    You can get this to some extent with any IMAP server, but Outlook/Exchange adds calendar, tasks etc which are also useful.

  • Tom

    OK, for me it hangs when I recive an HTML newsletter from CNN, everything else is fast, but displaying that one takes 10-20 seconds and my computer is SENDING information somewher because I see my LAN upload usage go up. I’ve read it has to do with “complex HTML”… Same message is quick in thunderbird or Opera Mail… so it’s Outlook’s fault.

  • Kieran

    (Internet Email Users – Not Exchange)

    May be worth compacting the .pst file you have – deleting the emails still leave you with a fragmented mailbox store.

    I copmacted mine and noticed a huge performance increase on Outlook 2007.

    Whilst not trying to teach the educated, to compact the .pst (Close Outlook first) then – Control Panel > Mail > Click Data Files, Double-click “Personal Folders” and choose “Compact now” – Then start Outlook. It’ll take a little while to get going, then it should be a touch quicker.

  • Tim

    Exchange users can compact as well.

    Tools – Account settings – Select Exchange and click Change – click More Settings – Advanced tab – Offline Folder Settings – Compact Now

    Almost as intuitive as syncing a public folder…

    Unfortunately it did not make much difference in my case.


  • Problem with RSS Feed in WordPress.
    I have a subdomain that I installed wordpress for another blog site, but the subdomain site's rss feed points to my parent site.
    Can anyone come up with any suggestions?

  • David

    I think the performance issues are with Windows XP. I have it installed on both XP and Vista going to the same exchange server. PCs are identical dell’s. On Vista it runs very fast, as fast as Outlook 2003 did if not faster. On XP it really slows down. Show to display HTML mail, slow to download messages (both PCs are setup to use exchange and download mail for 4 different POP3 servers. I have had no shut down issues but start-up time on XP is very slow. I wonder if Outlook 2007 was designed to run on Vista..???

  • Tim

    I think the performance issues are with Windows XP. I have it installed on both XP and Vista going to the same exchange

    This is interesting, thanks. I find Vista faster as well, though I get worse data corruption. I’m also not sure whether the difference is Vista, or clean install vs upgrade.

  • K Mills

    2007 with a 281meg INBOX PST and a 2.8gig ARCHIVE PST regularly hangs on SEND/RECEIVE and OUTLOOK shutdown. When restarting after this, it will NOT SEND/RECEIVE and you are required to open TASK MANAGER and manually END the offending OUTLOOK task. I have 10+ POP3 accounts being serviced, some SEND/RECEIVE fine, but it regularly hangs around 60%. LUDICROUS as 2003 worked like a charm. Time perhaps to look for alternatives, or roll back to 2003?????

  • Gus

    Had to Roll back not worth it for me, even that took 20 minutes on 3.0P4

  • Alex Woodrow

    I have similar gripes. I am running Outlook 2007 and BCM on a new Dell Core 2 Duo Laptop with 1.5Gb ram and Outlook is so slow its almost unsuable. I think its something do with the index search functionality and the fact that BCM is running SQL 2005. its a shame because the extra functionality is great. I like the way Outlook can now search all Emails, including my archive psts in particular.

    I believe that the maximum recommended size for a PST is 2.0Gb so exceeding that may be part of the issue for other users.

  • Paul

    The main problem I currentl have is downloading from a POP serve!?!? Outlook seems to disconnect and reconnect randomly while downloading messages. I have 110 messages on the server and it never gets them downloaded?!?!

    Running an Vista with no problems….only the POP!

  • Michael Mortensen

    Hello there,

    I completely agree here – my mailbox is >1GB and when i Send/Receive i can wait forever!

    Also, when organizing my mail, Outlook seems to hang for 20 sec. or so (moving mails from one folder to another).

    I never had these problems with the 2003 edition.

    Speaking generally (and I am a professional user of Microsoft software) it is my opinion, that the software released in 2006 has been of a quality I would not recommend to others.

    Is this a fair statement?

    I believe so – and when contacting Microsoft through various channels, you are somewhat ignored, but you have support from users – the customers of Microsoft.

    I am very troubled by this development, as I on a career basis have chosen Microsoft for my living bread.

    I guess I am out of context now, but to summarize: Outlook 2007 may appear nice and fancy on the UI part – but the functionality is decreased in quality compared with earlier versions of this product.

    The new functionality DOES NOT compensate for this 🙁

  • Tim


    I’m not sure how widespread the problem is beyond Outlook. But this is a real issue and I think we will hear even more about it next year when more people upgrade.


  • My .pst is about 2.7GB. Outlook 2007 is extremely slow but only when a send or receive is happening. I have a new Thinkpad T60 dual core with 2 GB ram. Nothing should slow this computer down. I consider it a bug, and will not permit it to be deployed in my company until they fix it. I have about 400 desktops.

  • George

    I have similar .pst size of about 3Gb. I’m on a relatively new/fast desktop with a 10rpm drive… 5 POP accounts…TWO major problems:

    1. As countless others are reporting, it’s very slow on the Send/Receive operation. Annoyingly slow.

    Interestingly, i did a big Send/Receive recently (about 400 emails) and after about 30 emails (or about 5 minutes in outlook 2007 world and being locked out of doing anything at all) I said stuff it, and hit Cancel on the Send/Receive. Then a few minutes later, i did the Send/Receive again, and like magic, it felt like Outlook 2003 again. The rest of the emails came down in about 1 minute. Can’t explain it, and have not had a chance to try again..anyone else?

    2. HTML emails are a big headache in outlook. Poor thing. It’s so hard to generate HTML these days! Again MS had to create a new rendering engine for it. Has anyone else noticed the great new features of this engine?

    a) By default, emails are more trusted for standard images, and show up without having to do the “download images” bit..great! but alas, now all background images have been completely removed! everything…body backgrounds, style backgrounds…everything… WHAT THE @##%? if you trust standard images, why not the BG ones? can someone please explain this wonderful theory to me?

    b) no more FORMS in emails! i will miss these. customer doesn’t even have option to trust emails and get the forms. I have a feeling this is where MS managed to slow down the rendering, as it tries to represent the fields with text. For example, instead of a radio box, they draw a () in it’s spot..etc.. who knows what else it is doing which therefore causes the slow HTML rendering.

    Anyway, I am on Aaron on this. Who in their right might would roll this junk out? This would cripple a business by loss of productivity. Yes, it sounds severe, but when I have to resort to hours of searching on the net for answers, I know I have a dud on my hands. Where is the “Outook 2007 Anonymous” support group? 🙂

  • Ken

    Guys, I found the problem!!

    IP trace shows OL 2007 sends an AUTH command as the first command to the POP3 server(s).

    The server has an immediate FIT and sends
    “-ERR An authentication mechanism MUST be entered”

    OL 2003 does not send AUTH – reater “USER ..” SO, who is going to take this to the Microsoft script kiddies. Looks like the real programmers have retired…. Sigh..


  • Tim

    Hey Guys

    Just confirming the existing of the problem.. again…

    I first came across it when I used the beta of outlook 2007 about 4 months ago on my old laptop. I’ve since got a new laptop (Duel Core 1.83gz / 2Gig Ram) with Vista and have just setup 02007 and have the same problems.

    The only thing that has stayed the same is my mail server –

    We’re running an Linux IMAP server, over SSL (self issued cert), over a 1gbs lan – and it takes around 10 min to do a send a receive, about 2-3 mins to open a single email.

    By contrast, thunderbird does this tasks in an “instant”…

  • Bruno

    Having similar issue with performance, running on an hp dv9000, 2gig ram, 2.0 GHz Core 2 Duo. 4gig local ost file. Outlook is very slow, almost to the point where it is unusable :(, Really sux.

  • Outlook 2007 is a disaster.

    Who the hell signed off on this as the RTM. This issue existed in the beta, I just assumed they would fix it by RTM, I can’t believe they released such a dud on everyone.

    The semi-painted windows take 3 minutes to display properly and it spikes the cpu to 100% which freezes the entire machine.

    Mail takes forever to download how could they not know about these issues ?

    Outlook 2007 is completely unusable at this point in time.

  • lukk

    Yeah, I got the same problem. I thought that Outlook 07 has a problem only with imap (aol) but as far as i see not only with that. I’m going back to OE or 03, cause this piece of trash is unusable

  • Matt

    Bruno…you are running a dv9000 series with windwos x64 ??????? if so you should PLEASE e-mail me at msmiielectronics @ yahoo with hwo you did it…I can’t get the NIC OR the sound working…..etc. etc..


  • Tom

    Wow. I finally found a thread where people are having the same issue as me. I thought that the freezing was hardware. Happens for a few seconds at a time. I read where if you turn off the ‘encrypt data to server’ it is a bit better and it is but not much. I also have about 1GB ost file. I even cleaned it out because of the problems I was having. I think its back to 2003 for me too.

  • Todd

    I’m not sure what all you guys are talking about. I have a corporation with 250 users, that I had migrate to all office 07 products – and its flawless. I have a 114mb ost. Duh thats what archiving is for. Anything over 100mb and you’re asking for trouble. I limit all our users to 150mb, the rest gets archived. Everything works like a charm – fantastically fast on a 1gbps lan.

    The only problem I’m having is searching public folders. Some of our post folders have 10,000+ records, and that takes maybe 20 seconds to search – and that is unacceptable to me. I did it on an office 03 machine with lower specs and it only took 2-3 seconds. Does anyone know why the searching of public folders is slow?

  • Tim

    Thanks for commenting Todd. It’s good to know that OL 2007 works well with small mailboxes.

    On the other hand, if OL 2003 is fine with mailboxes of several GB, but OL 2007 is not, that strikes me as a significant loss of functionality.


  • Todd

    Well after a bit of poking around yesterday. I watched the backend exchange server freak out when someone did a search in 07 on a public folder. One user did a search and spiked the server to 70-75% Just during the search. I have yet to determine if it does it in 03 also.

    I would imagine that if I defragmented the exchange public store. That would help also. I’ll keep you guys posted.

    Tim I would agree also that it is a loss in functionality – I’ve heard rumors its designed that way to force people into using Sharepoint.

  • John

    Having the same issue with Outlook 2007 RTM. I’m running a new Dell core duo 3Ghz with 2GB RAM. pst is about 600MB. All on XP Pro 32bit. On Send/Receive the computer is useless for about 2 minutes. I have 4 pop accounts and about 10 RSS feeds. I initially thought it was all the rules I setup to divert mail into folders (of which I have many!). But the issue is just getting the mail. Mine too freezes around the 63% mark.

  • George

    Me again. I have now -somewhat reluctantly- followed Todd’s advice to archive the main pst file. (although he refers to OST files which are used in combination with exchange). Not a big loss of functionality as you can still have the Archive file linked in and refer to it when you need it.

    Things that do improve:
    – General usability of outlook. It opens faster. Mails are accessed quicker.
    – Even HTML emails seem to generate faster

    Things that do not:
    – POP send/receive is still slow and locks up the computer for most of the time.

    I’m not so sure about those rumors either about SharePoint. If anything, that’s a bit of FUDD to turn the focus away from bad programming.

  • Todd

    Just in reference to John about the rules.

    I’m not sure how many you have, but I have 52 rules. Granted in my case those are all server-side rules beacuse I am on Exchange 2003. But the server still has to process that rule and route my mail accordingly.

    As another note. I did do a serach on a public folder in 03, and it took mere seconds, and the server performance didn’t diminsh at all.


  • Brett

    Can Outlook 2003 read the Outlook 2007 file? IOW, can I simply open the 2007 PST file in 2003?


  • Tim


    My understanding is that the PST format is the same for OL 2003 and 2007. So yes, you should be able to open the 2007 file in 2003.


  • Todd

    Brett: Yes you can they are now both unicode pst files.

  • I’m having the same problem running office 2007 on top of Vista on a brand new HP/Compag w/ 1.5 GB RAM and centrino duo processor. I’m only checking 2 POP3 mailboxes but my PST is 3.2GB. Anyone contact MS directly about this issue?

  • I can only say that my Outlook 2003 was OK, but after upgrading to 2007 its just been insanely slow. I can barely write an email, Outlook will hang while I type. Unbelieveable that my ten human fingers are faster than a computer capable of do millions of calculations per second…

    Anyway, trying to archive my 6GB ost file now, and keeping my fingers crossed. Its a nightmare. I am wasting 2+ hours daily waiting for Outlook.

  • John

    Todd – re: outlook rules – I have 61 rules and each diverts mail to a different folder in OL. Our company does not use Exchange, so I’ll assume those are all client-side rules. I never used OL 2003 so I have no comparison really. And it’s not as though I get THAT much e-mail. Each send/receive probably gets about 5 total e-mails/RSS updates.

  • I’m now using the production version of office 2007 and I truly thought the performance problems with Outlook would be fixed. Unfortunately, no such luck. I’m running a Core 2 Duo laptop with 1 GB RAM, so hardware is not the issue. Microsoft has truly gone to hell in a hand basket. Damm I hate greedy monopolies. Why can’t some third-party come up with an Outlook killer for Linux or even Windows??? Thunderbird is nice for mail, but I need calendaring that works with Outlook message requests.

    Have to say that I’m really pissed at Microsoft for doing such a pitful job at “upgrading” Outlook. What do Microsoft planners do in meetings? Hey I have an idea, lets make it really slow so that people will hate us?? Where do they get these people? Idiots.

    Sorry for the rant.

  • Jumped the gun slightly on Vista, by purchasing a ne 64 bit workstation (dual quad xeon) costing more than my wifes last car did NEW. Out of the box, very quick. It’s got 16Gb of RAM and 3Tb of raid drive storage. Initially installed (by Dell) Win XP64. Installed Office 2007 and installed Outlook 2007 with some difficulty as we had problems the server name (we have a split domain network). A colleague sorted that out for me and OK’d the search indexer.

    Outlook 2007/Windows fast desktpo search has turned a current top of the line workstation into a bumbling idiot, and I have had to use my 3 1/2 year old twin Xeon machine with 4Gb RAM and 2003 just to delete an email!

    We run an Exchange 2003 server and I have a 10Gb .OST file, we develop sports web sites, and I file back up emails from web forms, client correspondence etc I use the 30 or so rules you could fit onto Exchange 2003.

    I have left my machine (it was useless for anything else) indexing for the past 24 hours, it eventually said all my folders were up to date, and I “snoozed” off the bloody irritating desktop search (which I dont need, I know where all my files/folders are). Even when I exit Outlook, it is still indexing in background, even though the folders were up to date, Since rebooting this morning Task Manager tells me that Outlook.exe*32 has performed over 35,000,000,000 I/O Read Bytes.

    Not happy at all. I am now trying to compact my .OST file.

    In frustration I even looked on the Ms online help, they were talking about over £150 per incident, sorry that would now be about £350 as it is after hours, no guarantee of a resolution, and all I wanted to tell them was how pants Outlook 2007 was.

    I remember how when we upgraded from Exchange Server 5.5 on a Pentium II which worked fine, to a spanking Pentium IV with 20 times the RAM, it was about 10 times slower…

    I think I am going back to Office 2003 as 2007 is lobotomizing my workstation and strangling my work flow, even when I exit….

  • Uninstalled Windows Desktop Search 3.0 and this made things slightly better, which meant I could use the machine for about 30 seconds in every 180…

    Now uninstalling 2007 completely.

    IMHO this software was not beta tested in a broad enough environment. Anyone know if it is any better on Vista? This whole experience is making me very, very wary of even attempting to install it.

  • Todd

    I can’t find any correlation here at all. I have installed Office 07 standard on 59 computers with Win XPsp2. The computers are Lenovo Pentium D 2.8, with 1.5gb of ram, and a 120gb sata 3gb/s HD. They haven’t said one word to me about it being slow. In fact many people love it. My personal computers include an IBM T60 CoreDuo (not 2) with 2gb of ram on Vista Business RTM – office 07 with Aero – 0 problems. My other machine is an IBM Zpro dual 3.2 Xeon with HT, 4gb of ram, scsi320 73gb HD on Vista Business RTM. I have 0 problems with that one also.

    I think the single problem here is the fact that OL2007 was probably made for mapi mailboxes and support for pop went by the wayside. Maybe they figured OLX, and Thunderbird were for the junkies who wanted pop access anyways.

    I am thinking if you are on a LAN with Exchange you’ll be fine no matter what your specs are. Anything else and I belive your SOL. =/

  • Tim


    The “correlation” is the size of the mailbox (I suspect). Essentially, OL2007 gags on mailboxes that were fine with OL2003.

    Many of the commenters here are using Exchange; that’s not the issue.


  • David Rosselott

    Hi guys. I’m noticing problems in Outlook 2007 based on the number of e-mails present in a mailbox. My Exchange mailbox isn’t terribly large in size or in the number of e-mails. OL2007 seems just fine with it.

    However, if I check a mailbox that exists to receive alerts on my network, OL2007 just bogs down like mad. The overall size of the mailbox isn’t tremendous, but it contains 1000’s of tiny alert e-mails going back a year or so. Should I archive these and clean up? Sure. But trying to use OL2007 for that would be frustrating in the extreme. One would think 2007 should be at least as useful as 2003.

  • Andy

    I am having the same problem. After upgrading from 2003 outlook to 2007 outlook, everytime a send/receive happens my pc freezes. I can’t do a single thing when it’s frozen. It has nothing todo with the number of rules i have setup or the size of my pst files. Microsoft f’d up. Plain and simple. Looks like we’ll have to wait till a patch is made available from them. I havn’t come across a post from anyone on the internet with a solution. Anyone here at my office that has upgraded has the same problem. I added more memory to my pc to see if it would speed it up….no go. Same lag, no difference at all.

    I’m bookmarking this page hopefully someone finds a workaround, backdoor fix soon because it’s driving me nuts.

  • Ed

    I’m disgusted by the performance issues I’m seeing with Outlook AND with Word after installing Office 2007

    Has anyone noticed that if you open two Word files and you Alt-Tab between them, the CPU runs to 100% and you get the hourglass for about 2 seconds? This did not occur with Office 2003.

    I’m curious to know what else everyone’s seen.

  • Ed

    My Solution Has Been Resolved!

    Remove Acrobat PDFMaker Office Com add-in from Word 2007.

    In Word 2007, Under Word Options, then Add-Ins – Remove Acrobat PDFMaker Office Com Addin, if it had been downloaded from Microsoft. I believe the Office 2007 Beta 2 had this functionality built-in, or at least when you downloaded it the add-in was already available.

    I also suspect that removing other add-ins may also impact the CPU problem I’ve described above.

    After I took the PDF add-in out, Outlook performance and Word performance improved.

    I will turn the add-in back on when I need to save a Word document in .pdf format. Immediately thereafter, I’ll take the add-in out again.

    I certainly hope this post will be helpful to others.

  • Andy

    Ed…..Your send/receive in Outlook 2007 has been fixed?

    I don’t have this addon your talking about.

  • Andy

    Nevermind….I just read your earlier post.

  • David

    I was searching because my Outlook 2003 is horribly slow when downloading from a POP3 server. This has always been the case. I have tested using different email clients and either Outlook Express or Eudora can download a 100 messages in about 10 or 15 seconds. Those exact same 100 messages will take 3 or 4 minutes in Outlook 2003. And why can Outlook not multi-task while downloading? If it is downloading anf I click on a message it takes forever to respond, but if I double click the message it opens right up. Any suggestions would be greatly appreciated. My pst file is 730 MB.