Search e-mail at lightspeed: using Lookout with Outlook 2007

Everybody who uses Microsoft Outlook must know that Outlook’s search functionality sucks. Yes, I know that’s a bold statement, but there’s no other way to say it. Outlook search sucks big time, period! Even Joel agrees… My mailbox is growing every day and I find it harder and harder to keep track of its contents. A search through my archived folders often takes a much as a full minute of searching, which I find unacceptable. In the press I often read Microsoft Corporation finds Search important and lately we’ve seen them release some impressive search products (i.e. Search Server 2008 and Search Server 2008 Express). Also a major part of my daily job involves implementing SharePoint 2007 solutions at our customers, which most of the time also includes SharePoint’s search feature. But somehow the Outlook team seems to have missed the boat…

Some years ago a guy called Mike Belshe created a great free Outlook add-in called Lookout, that offered a lightning fast search. Within seconds of starting a search (often even within a second!) the results would appear on screen. Microsoft was quick to buy his company and its technology. At that time many people expected Microsoft to integrate Lookout into Outlook, but unfortunately they seem to have shelved it (Mike himself claims some of his Lookout code ended up in Windows Desktop Search). So now there’s no official way to obtain Lookout. Luckily there are many sites that still offer the Lookout download. A quick search on Google should point you to some sites containing working download links.

However, getting Lookout to work with Outlook 2007 is more problematic. It turns out that Lookout checks for specific Office Primary Interop Assemblies (PIAs) and the PIAs that come with Outlook 2007 don’t pass this test. The result is that Lookout prevents itself from running under Outlook 2007 and instead displays this warning message:

Lookout error message

After much demand Mike Belshe published a way to get Lookout to work with Outlook 2007. For this you have to rename an Office PIA file, which resides in the Global Assembly Cache. While this solution gets Lookout to work, it may have serious impact on other applications/add-ins that make use of this PIA. So this solution isn’t acceptable for me (and it shouldn’t be for you!).

Instead I opted for a different approach. The only reason that Lookout doesn’t run on Outlook 2007 is that dreaded PIA check. So why not remove it? Which is exactly what I did…

A quick Reflector session revealed that the code that performs the PIA check is located inside the assembly named Inventures_Olk.dll and goes by the name of CheckOutlookInterop(). What it does is compare the installed Office PIA’s name to a built-in string constant. If the match is positive it returns the boolean value true, otherwise it returns false. Using ILDASM I decompiled the assembly to CIL, changed CheckOutlookInterop()‘s code to always return true and recompiled the assembly. So that gave me a fully working Lookout version that’s compatible with Outlook 2007!

You can download the patched assembly here. Just replace the the original Inventures_Olk.dll with the patched version and you should be searching your Outlook 2007 content a lightspeed in no time…

Oh yeah, there’s one small issue… It seems Lookout crashes while indexing if you run it on Vista. Bummer…

Update: Recently I discovered there’s another bug in Lookout that causes dates to be parsed incorrectly if you have the .NET Framework 2.0 installed. You can read more about it here. Fortunately someone has fixed this problem and also released a patched DLL that you can download.

Update 2: The DLL I patched and offer on this blog should work with Lookout version But as I understand that version of Lookout crashes during indexing on Vista and Windows 7. In the comments below user Stroth claims he got my patched DLL working with an older version of Lookout, a version that also works with Vista and Windows 7 and doesn’t crash. That’s good news, however I never tested that.

Posted on January 22, 2008, in microsoft, search and tagged , , , , , . Bookmark the permalink. 166 Comments.

  1. Please please, can someone upload Lookout 1.2.8? I cant find it..I have outlook 2007 w Win Vista 32-bit and lookout crashes when beginning to index!

  2. At work, I upgraded recently to Vista Enterprise SP2 and Outlook 2007. I, too, found that Outlook’s standard search is uselessly slow, especially considering that I had been using Lookout on XP Pro with Outlook 2003.

    I found LookOut 1.2 and downloaded it and installed it (without Oulook 2007 not running). I then replaced lookout.dll and inventures_Olk.dll. I then loaded Outlook 2007 and Lookout is indexing right now.

    Thanks, everyone!

    It’s amazing! When something works and works well, we don’t want it being messed with, and we don’t want to mess with trying something new.

  3. xp sp3, outlook 2000 sp3, lookout 130: was working great until a few days ago. then the toolbar shows; but just a stub…no words..very short in length. any ideas welcome. log shows:

    3/26/2010 5:58:29 PM Starting up
    3/26/2010 5:58:29 PM Caught exception loading assembly (C:Program FilesLookout SoftwareLookoutLookout.dll): System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.TypeLoadException: Method ‘get_Icon’ in type ‘Chrome.AddInInfo’ from assembly ‘Lookout, Version=, Culture=neutral, PublicKeyToken=null’ does not have an implementation.
    at Chrome.AddIn..ctor()
    — End of inner exception stack trace —
    at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck)
    at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache)
    at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache)
    at System.Activator.CreateInstance(Type type, Boolean nonPublic)
    at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
    at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
    at System.Reflection.Assembly.CreateInstance(String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
    at System.Reflection.Assembly.CreateInstance(String typeName)
    at LookoutAddIn.Connect.OnConnection(Object application, ext_ConnectMode connectMode, Object addInInst, Array& custom)

  4. My lookout problem was caused by some corruption of the .net frameworks on my system. I used the “.NET Framework Setup Verification Tool User’s Guide” from to verify the problem and verify the reinstalls were successful.

  5. Got it working quite easily on Windows 7 x64 home with Lookout
    This is what I did:

    1) I Installed outlook 2007
    2) Disabled indexing in outlook (not sure if this is needed)
    3) Shutdown outlook
    4) Installed lookout 1.3.0
    5) Replaced outlook.dll
    6) Replaced Inventures_olk.dll
    7) started outlook.

    I got a couple of crashed on indexing regardless of all tips above (empty deleted items, lowest agressiveness), so I decided to try without any folders selected:

    8) I deselected all files and (mail-) folders for indexing.
    9) Then I ran the indexer once (blazingly fast . .) which for the first time succeeded.
    10) After that I selected inbox and other folders,
    11) started reindexing which now went through without issues.

    I have not had any issues since, and am searching at LightSpeed once again!

  6. Solution described above worked like a charm for me too in outlook 2007.

    Found the offending dll in the lookout software folder in C:
    Renamed it with …_old just in case and dropped the patched dll linked above in same folder;
    Restarted outlook.
    Lookout started and built the index and is working beautifully.

    Thanks very much !!

  7. Replacing the DLL was a perfect fix and I will be eternally grateful for this patch!

  8. Valdorious Boneflect

    For Outlook 2007 on Vista/Windows 7 users, you might find the information on this link useful:

    along with the changes to PIA names, it got me to a working, stable install of LookOut on Outlook 2007.

  9. I ‘ve been using lookout for years now, also on Outlook 2007 using the workaround of renaming Microsft.Office.Interop.Outlook

    but all of a sudden, the search field of lookout was gone. Uninstalled and re-installed doesn’t help.

    Replaced also Inventures_Olk.dll, but still doesn’t help. When I start Outlook, the lookout window doesn’t pop up, nothing.

  10. I have lookout functioning perfectly at fully aggressive indexing speed on Outlook 2k7 under Windows 7 Pro. I posted on this blog about how to do it, but apparently because I also took the opportunity to chew out (without profanities) the Lokeen spammers for subverting every lookout thread they could find with their blatant advertising, my post was deleted. So, I’m not gonna tell you how to do it, and thank the mods for that 🙂 I’ll give you a hint though – you have to disable a default windows service. Good luck!

  11. @Lee: I can’t remember deleting one of your posts. Please share your fix with us.

    I do run an automatic spam filter, which may have mistakenly identied your previous post as spam and deleted it.

  12. Okay, sorry for my misassumption. I can’t reproduce the break now that I’ve fixed it, so I’m not TOTALLY certain what it was I did to accomplish the fix, but I basically remember what I did so it must have been one of these things since it was crashing consistently for days no matter what I did previous to the fix.

    I went to %appdata%MicrosoftOutlook in my profile and blew it all away (it recreates itself anyways.) I then went to Outlook -> Tools -> Trust Center -> Addins -> “Go” (to manage COM addins). Within the resultant dialog, I disabled the following addins:

    Calendar Gadget for Windows SideShow
    Microsoft Office SharePoint Server Colleague Import Add-in

    I attempted to disable Windows Email Search Indexer as well, but I was unable to do it from there due to administrative settings. I then went to my services control panel (run services.msc,) stopped the Windows Search service and set the startup to disabled. At this point Lookout started working with flying colors at full aggressiveness, no logs, no indexing of attachments or file contents (dunno whether that would work, I haven’t tried it.)

    Before posting this I undid all of my steps – restoring the files I had removed from appdata, re-enabling all of the COM addins, setting Windows Search service to automatic and starting it, and everything is still working.

    If you’ve ever seen the Dr. Seuss book where a North-going Zax meets a South-going Zax in a desert, and each of them refuses to budge for the other to pass, and an entire civilization grows up around them while they are standing there stubbornly, that is kind of analagous to my best guess as to why this wouldn’t work before but works now – I think the search indexers were conflicting with each other while trying to accomplish a specific portion of their indexing. Disabling the South-going Zax allowed the North-going Zax to go on his merry way and get to his destination, and then once re-enabled, the South-going Zax was able to get to HIS destination as well, and everyone was happy. It’s voodoo, but that’s the name of the game where making lookout work is involved 🙂

    Hope this helps someone!

  13. Hi,

    When I tried to download STROTHs package Rapidshare said that it has already been deleted. Can anyone help by providing me another copy of it? Thanks very much.

  14. Many Mirrors for Downloading Lookout v1.2.8 >>>

  15. Your solution worked brilliantly – I was ecstatic but then it only worked for a while.
    I am on XP Pro, with Outlook 2007 Standard SP2.

    Outlook has been crashing and going very slowly. It comes up with error message (with option to send to Microsoft). When Outlook restarts, the reading pane has been turned off. Events viewer says the module causing the problem is unknown.

    I have gone Tools, TrustCenter, Add-ins, and disabled Lookout under Com Add-ins. As of now it all seems stable again. But I don’t have LOOKOUT!!!

    I have followed Leon’s solution above a 2nd time, but end up with the same result as above.

    Any brilliant ideas?

  16. After a short stint using Lookeen and outlook search on Outlook 2010 I decided to reverted back to lookeen again. Got working on Windows 7 x64 with Outlook 2010 ! Roughly in the same manner as I explained earlier.

    1) I Installed outlook 2010 (32 bits)
    2) Disabled indexing in outlook (still not sure if this is needed)
    3) Shutdown outlook
    4) Installed lookout 1.3.0
    5) Replaced outlook.dll
    6) Replaced Inventures_olk.dll
    7) started outlook.

    I got a couple of crashes on indexing regardless of all tips above (empty deleted items, lowest agressiveness), so I decided to try without any folders selected:

    8) I deselected all files and (mail-) folders for indexing.
    9) Then I ran the indexer once which succeeded(blazingly fast, again . .)
    10) After that I selected inbox and other folders but it crashed
    12) then I moved the index aggressor to minimal but one and it crashed
    14) then I deslected all folders and chose one folder in one of my mail archive folders (pst file) and moved the index agressor to the absolute minimum.
    15) and the indexing started to work.
    16) once indexing was completed I put the index aggressor to max and it worked.
    17) but when I added a new folder I had to revert to minimal index speed again.
    18) So I indexed all new folders once on minimal speed once, and that seems to work

    It seems that the key thing is to move the index aggressor to minimum for new folders. Once indexed once, there is no issue moving the agressor up to max again.

    Outlook 2010 created new tabs for add ins, so you don’t have lookout immediately available, however you can add Lookout to your “quick access toolbar” with one right mouse click, and that is almost just as good.


  17. Success! I followed Erik’s instructions and I am now running Lookout on a 32-bit Outlook 2010 installation, running on Windows 7 Professional x64.

    To clarify things a bit: once the Lookout wizard pops up for the first time, disable automatic indexing and set the index aggressor to minimum. This means you will have to manually choose to re-index stuff, but I usually only do this once a day if something I’m looking for doesn’t pop up in the index.

  18. many thanks!! I was crazy as my new laptop is with Windows7 and Outlook2007 and Lookout did not work.
    I tried Mike’s fix but did not work for me as I was unable to rename the interop files. Surfing again and again, i found this blog and applied both patched dll + the appupdate.log manual creation and now, i’m the happiest user!
    I promote Lookout in my team and everybody is using it on a daily basis. For now we are 2 with Windows7 and i’ll tell my colleague how to make Lookout working again hopefully. Thanks again to all of you and special kudos to Leon and Solomon waters!

  19. best solution is the Inventures_Olk.dll replacement. Better don’t use the Microsoft.Office.Interop.Outlook renaming (what results in an automatic replacement by an older version of it).

    One word to crashing, not indexing etc. :
    1. Don’t tick macrosecurity for your addins. By default it is unticked anyway
    2. Reset ur toolbars, untick lookout, restart outlook, tick lookout
    3. Lookout of cause can’t index IMAP Folder Contents

    Thanks very much for this workaround!

  20. Thanks — simply replacing the .dll file with the one in the download here ( worked like a charm!!

  21. After replacing the 2 .dll files, LookOUt worked like a charm for me. Thanks for this great post!

  22. Thanks for that great patch and its documentation!!

    I followed Erics instructions (October 14th, 2010 at 13:37:43) using the following software:
    Lookout 1.3 (
    Office 2010 (
    WinXP 32bit sp3

    I added the following steps to get Lookout working:
    1-4) as Erik described
    5) Replaced lookout.dll
    6-8) as Erik described
    8a) Restart Outlook
    9) as Erik described
    10) I selected the mailfolders of my pst-files, increased the index aggressor, started the indexing and everything worked fine

  23. Thanks so much for helping me carry on with Lookout on Office 2007. It’s been working well for the most part but from time to time, when I try to drag a message from the lookout box to attach to an email I get the error “Cannot find this file. Verify the path and filename are correct”.

    Re-indexing from scratch fixes the issue but wondering if anyone has any idea what causes it, or how to avoid? I never saw this with Outlook 2003.

  24. @Matthew: I’ve seen that message too. I think what it means is that the Outlook object (Mail message, calendar item, etc.) has been moved after it was indexed by Lookout. This could be due to an Outlook Rule or automatic archiving. The latter being the reason it failed on me. Did you set any of these?

  25. Hi Leon – thanks for the speedy reply and sorry for slow response. Yes, you are correct that it seems only to happen with objects that have been moved after Lookout indexing. I don’t use Rules or automatic archiving, but when I hit up against my company-imposed Inbox size limits, I manually move mail over to separate .pst folders. This was never a problem with Office 2003 and 2007 was fine initially, but now I can no longer drop these .pst items from Lookout search onto a new email.
    And contrary to my original post, re-indexing from scratch doesn’t even fix the problem so it’s a lot worse than I thought. I think last time I must have re-installed Lookout to fix it.

  26. I’m currently using lookout 1.3 in Outlook 2007 on Windows 7 32-bit. After installation it crashed Outlook as soon as it started indexing. Turning of antivirus (NOD32) fixed that problem. After the indexing was done I switched on NOD32 again to test some stuff and now it seems it can index without crashing.

  27. Conozco un plugin para Outlook que es muy bueno para encontrar archivos adjuntos, y conversaciónes en Outlook, se llama Lookeen

  28. Running Windows 7 Enterprise 64, have tried both Outlook 2010 and 2007 with Lookout 1.3. Still getting the crashing on index issue, even after trying the following:

    -replacing both Inventures_Olk.dll and Lookout.dll (separately)
    -renaming the Interop libraries (not able to do this with Office 2010)
    -removing the Deleted Items from the indexing (weird, but ok)
    -lowering the aggressiveness of the indexer
    -running the indexer without any folders selected (worked, but when a single folder was added it crashed everytime)
    -running Outlook as administrator
    -turning off UAC altogether (pretty sure this set off sirens with the PC team at work, but I didnt get in too much trouble 🙂

    I did get this working with both Outlook 2007 and 2010 when I was on XP Pro, so I have to assume there’s something with W7 thats killing this.

    I’m basically able to do anything to this machine (short of a full reinstall), so willing to do whatever it takes to get this to work. Any help would be GREATLY appreciated – thanks in advance!

  29. I think I found the solution for Lookout 1.3 + Outlook 2007 + Windows 7. Seems like 1.28 and 1.3 are not as graceful as 1.20 when it comes to the missing AppUpdate.log file. I installed 1.3, copied the two dlls, and then created the log file. I was able to re-index without Outlook crashing.

    Good luck!

  30. I can’t even install the lookout. (XP Pro SP3 + outlook2007)
    I tried v1.2, v1.28, v1.3, but all failed.
    It stopped at extract lookoutAddIn.dll.
    The detail info showed:
    Checking platform requirements
    Checking for Microsoft.NET Framework 1.1
    Installing lookout files…
    Then, after 30min, it still showed installing lookout files…

    Anyone help !!??

  31. @Matthew,

    Were you able to find any fix? I too have this issue and it makes the whole purpose of a faster search not usable. 😦
    I hope someone has a quick fix.

  32. One more thing I’ve noticed is, the search results are pointing to %tmp%/.msg link.And thats why outlook says the file is missing.

    So,is lookout just creating a symbolic link?

  33. I too have been having issues with Lookout crashing on Windows 7, 64-bit, Outlook 2007.

    Oddly enough, somehow the issue seems to be traced to me running dual monitors through my laptop docking station. I have no idea why that would be. All I know is that forcing an index with 2 monitors crashes immediately. Take laptop off docking station and the index happens perfectly.

    Might be worth a try if you are running 2 monitors.

  34. Trilok Khanna

    Thanks a lot Mike. The solution you have provided to copy two “inventures_olk” and “lookout.dll” file in C:Program FilesLookout SoftwareLookout folder worked great for me. The lookout is working ok in my windows 7 workstation(Office 2007).

    Thanks for the help.

  35. The same issue as Jason:
    I have downloaded the Lookout install package from two sites and keep having the same problem. The install starts then stalls out at Extract: LookoutAddIn.dll , I have 1.1, 2.0, 3.0 & 3.5 &4.0 .NET installed. Any solution? or Is there any portable version that can bypass the installation?

  36. Windows7 + Outlook2010 + Lookout1.3 + Patch and then disable Windows Search Service – This works for me.

  37. Rico Pagliuca

    Cyger… really? I am on same setup. No windows search service enabled, both patched .dll files, and I get a crash any time I voluntarily index.

    I have created the accesslog.log file and disabled all other add-ins except exchange. I’m currently only trying to index a .pst file in it with 200 mail items, and I’m attempting at minimal resources.

    Crashes every time ;__;

    I friggin LOVE this program, I love that enough of us know about it and want it to work so badly.

    I will do absolutely anything to get this working.

  38. Rico Pagliuca

    Also, I cannot find a 1.2 installer for lookout anywhere. I can find 1.28 but not 1.2

    pleeeeeeeeeeeeeease help

    my email is

  39. Cyger’s fix works!
    Windows7 + Outlook2010 + Lookout1.3 + Patch and then disable Windows Search Service
    Be sure to follow the patch instructions:

    Install Lookout 1.3

    Open a command shell (run as administrator), and issue the following commands:
    • cd %SYSTEMROOT%assemblyGAC
    • rename Microsoft.Office.Interop.Outlook Microsoft.Office.Interop.Outlook.OLD

    replace the following dll’s and file created during install with these dll files.

    See Mike’s entry above (Luv U Lil Bro)
    March 3rd, 2008 at 17:08:18 for links to the new dll’s

    (AppUpdate.log is just an empty text doc you can create in notepad and save as AppUpdate.log)

    Disable Windows Search Service and RE-boot!

    If you are still struggling with WIN7 + Outlook 2007 follow these instructions, however no need to disable Windows Search service

    Thanks Leon for keeping Mike’s Lookout alive. I know he has no idea how addictive it is. Once you have Lookout, you can’t use Outlook without it.

  40. Rico Pagliuca

    I have done ^^ EXACTLY ^^ that. Step by step. Windows Search disabled, dll replacement… Still crashes when I index on OLK2010/Win7/Lookout1.3 😦

    whyyyyyyyyyyyyyyyyyyyyyyyyyy ;____;

    I am truly desparate. If I could get this going, it would be a huuuuge win.

  41. Echo Rico’s post.
    Lookout never gets into indexing. As soon as it starts Outlook crashes
    W7+Outlook2010+Lookout 1.3
    Any help is greatly appreciated.

  42. hihi..I tried to rename the file, but says “access denied”. Any ideas?

  43. Is anyone successfully running win7 x64 w/ outlook 2010 x64 w/ Lookout or will only the 32-bit versions work?

    I had no problems getting it going with Outlook 2007 on XP but have just upgraded.

  44. @Matthew

    I have the same issue. It happens for things that are in my Inbox as well (i.e. they have not been moved). The workaround, which is not as convenient as simply drag/dropping the item from Lookout results into a new email as an attachment, is to make note of the Date and Folder in the Lookout results, go to the email where you want to insert the attachment, and use the Attach Item button to locate the same message using the Date and Folder info Lookout provided. Too bad drag and drop does not work …

  45. I have Lookout working on Outlook 2007 / Windows 7 64bit. I replaced both dll files mentioned above. Outlook would crash on indexing but reducing the “Indexer Aggressiveness” under Lookout options – Advanced fixed this.

  46. I’m having the crash issue as well and followed Eric steps above (and others). Although there was a period of time where I did not have the crash issue, and at that time I created another Outlook profile for a different user who was sharing my system, AND when I start Outlook with this other profile the indexer will not crash Outlook. Therefore I believe the core of the crashing issue is either a corruption issue with the actual Outlook profile or the Lookout profile/files that Lookout creates. I’ll keep everyone posted if figure out anything, but for those of you who are having problems you may want to

  47. Hi,

    I have lookout 1.3 running with XP & outlook 2007 but after indexing all my search results are returning no results !?!?!

    All I’m trying to do is search a keyword, am I doing something wrong ????

    Any help appreciated.


  48. Thank you! This method work like charms!

  49. @Rico Pagliuca
    Try to change the location of data folder in Lookout to e.g. c:Temp

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