How to Install Lookout on Outlook 2007

I got another request today from an old friend for how to make Lookout run inside Outlook 2007.  I’ve probably received a thousand such requests over the last few years…  Since I recently installed Outlook 2007, I finally was able to test it out. 

This fix should make Lookout work.  However, if you have other .NET addins running in Outlook, there is a chance they will no longer work.  The fix is reversible though, so don’t be too scared.  But this fix is definitely for the tech savvy.  Gory details:


Installing Lookout on Outlook 2007

1) First, you’ll have to find a copy of Lookout.  Microsoft doesn’t distribute it anymore, but issuing this search on Google seems to find it pretty handily.

2) Next, install Lookout.  You’ll need admin privileges (no difference from XP), and the install will go without a hitch.

3) When you next restart Outlook, you’ll probably get this very apologetic-yet-unhelpful error dialog:


4) The problem is that Outlook 2007 ships the Outlook 2007 Office PIAs by default.  Open a command shell (as administrator), and issue the following commands:

  • cd  %SYSTEMROOT%\assembly\GAC
  • rename  Microsoft.Office.Interop.Outlook  Microsoft.Office.Interop.Outlook.OLD

5) Restart Outlook and you are good to go.


If this doesn’t work for you, or it breaks some other plugin, you’ll want to restore the interop library.  Just undo the command above thusly:

  • rename  Microsoft.Office.Interop.Outlook.OLD  Microsoft.Office.Interop.Outlook


Why does this dialog exist?

Only read this section if you are an Outlook plugin geek!

At the time Lookout was written, Microsoft’s strategy for shipping PIAs hadn’t fully been sorted out.  Prior to Outlook 10, there were no official PIAs.  Outlook 10 introduced official PIAs, which you could redistribute.  Outlook 11 had official PIAs as well (different ones), but Microsoft didn’t permit redistribution of them, and they weren’t backward compatible.  Further, with VS2003, it was pretty easy to create your own PIAs, which were almost identical to the official ones, but not signed.  There were lots of plugins out there, and some of them handled PIAs badly. 

At some point, Lookout ended up requiring that it be able to find the official Outlook 10 PIA installed, or it would assume it would fail.  It wasn’t smart enough to recognize that new versions of the PIA might be legit, and probably should have handled it better.  Who would have guessed that Outlook 12 would introduce yet a 3rd PIA distribution strategy?  OL2007 elects to install the PIAs into the GAC by default; so plugins no longer needed to redistribute them at all.  I do believe this is the best strategy.

What this simple fix does is temporarily uninstall the Office 12 version of the PIA.  As long as no other .NET Outlook addins are running (C++ based addins don’t use PIAs), this has absolutely zero negative impact on your system.  If other .NET addins exist on your system, and those addins are Outlook 11 or 12 specific (I don’t know of any OL12 specific plugins yet?), then you might have a problem with this fix.  These conflicts should be rare, but not zero.

Anyway, search on!

BTW - This fix is thanks to the Wayback Machine!  The original lookoutsoft support article ( is now long gone.  But the Wayback Machine had it!  Otherwise, there is no way I would have remembered what the heck this error was about.

Related Blog Posts:

Thanks to Rohan Deshpande for consolidating updated instructions from the comments posted here. On some systems, the above instructions need to be augmented with two more steps:

 * echo ” > Microsoft.Office.Interop.Outlook
 * rename Policy.11.0.Microsoft.Office.Interop.Outlook Policy.11.0.Microsoft.Office.Interop.Outlook.OLD

178 Responses to “How to Install Lookout on Outlook 2007”

  1. Great! Al fifteenth tenttivo has worked on a Win7 with Outlook 2007 sp2. The combination that I have tested is the rename of Microsoft.Office.Interop.Outlook in an old file and the substitution of the dll Inventures_Olk.dll and Lookout.dll in C/:Program Files/LookOutSoftware/lookout.
    N.B. The versione of LookOut that works is the 1.2 (the 1.3 versione crash when start the indexer).
    Tks U!

  2. Irel says:

    Just got lookout 1.3 working with Windows 7/Outlook 2007 by -
    1. Emptying deleted messages in outlook.
    2. Disabling index option in Outlook. Then log out.
    3. Install Lookout 1.3.
    4. Change file to Microsoft.Office.Interop.Outlook.OLD
    5. Open Outlook and reset index by clicking on folders to be indexed.
    6. Lower Index speed to about half and you should be set.

    The indexing will take about an hour or two depending on the size.

  3. kettingshop says:

    Lookout on Outlook 2003 on Windows 7:

    I experienced the same crashes as mentioned above. I have solved the problem only by installing Lookout 1.2.
    Version 1.3 and 1.28 both kept crashing.

    Lookout 1.2 reports an error as mentioned above with the missing AppUpdate.log file. Simply adding a new, empty text file in the directory that is written out in the error text fixes this.

    I did rename the \assembly\GAC\Microsoft.Office.Interop.Outlook, it worked for me in Windows Safe Mode (press F8 when starting Windows). I do not know if this has had any affect: Outlook has created a new file with the same name.

    After an hour and a half of hacking, I will now begin to see if Lookout is as good as people say… ;-)

  4. Jun Kan says:

    Thanks! i followed your procedure and now Lookout1.3 works in my Outlook 2007 in Win7 64. My Outlook at first became nonresponsive 3 or 4 times. I removed the indexing for “Deleted items” and “RSS feed”, then allowed outlook to finish indexing.

  5. Jun Kan says:

    I mean, “LOOKOUT to finish indexing”. Sorry.

  6. tispratik says:

    Thanks for posting this article! It really helped me get Lookout running.
    After reading your article i upgraded from Outlook2003 to 2010, but Lookout did not work there. Then i downgraded to 2007, it did work there!

    Lookout is the only reason why i had not upgraded from 2003 to 2007 in the last two years, but now since i know that i can get it working, i did upgrade :)

  7. toutchoc says:

    Being completely in trouble with the outlook search, I just installed Lookout 1.3 on my Outlook 2007. Surprisingly, it works very well without even doing the rename mentioned in your post !!!

    Maybe microsoft has made recently some update that makes this rename no longer necessary. Or maybe it is because I’ve deactivated the Windows search service…I don’t know. Anyway, my advice is now to try installing Lookout without doing the rename first. An do it only if it’s not ok.

    Anyway thanks for this post. I had Lookout in the past, and since 2 years I used the slow built-in search of outlook 2007 until it definitively refused to work despite all my efforts and research. Coming back to Lookout is a pleasure.

  8. 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!

  9. smartaus says:

    Mine is Windows 7 64 bit and Outlook 2007. Installed Lookout130 – crashes on indexing. Anyone had success?

  10. First Name, says:

    anyone pls HELP! I got a new laptop at work with Windows 7 and Oulook 2010. I need my Lookout….pls :-( Does anyone have step by step workaround and place for Lookout download? Please, please….e-mail: Mike F.

  11. First Name, says:

    I tried per above comments and nothing work. Can anyone help with step-by-step Lookout installation for Outlook 2010 on Win 7 64 bit? Thanks in advance

  12. guys, can you please advise where can I download lookout 1.2? I need this version to make it work with my windows 7.

  13. yair says:

    Env. Win 7 64 bit , Outlook 2007

    steps – these steps worked for me
    - install lookout version 1.3 and start outlook get error msg verify that you see lookout toolbar
    - go into safe mode – just unplug the compurt from power and it provide an option to go to safe mode
    - rename GAG in cmd – see belwo how
    » cd %SYSTEMROOT%\assembly\GAC
    » rename Microsoft.Office.Interop.Outlook Microsoft.Office.Interop.Outlook.OLD
    - start outlook – if all is fine – that’s it
    if not
    - start outlook and uncheck the lookout toolbar and close outlook
    - start outlook and check the lookout toolbar back

    start working …

  14. cryingtiger3 says:

    Anyone know how to make Lookout work on Outlook 2007 that is running Windows 7 or Vista? I’ve tried everything here and it does not seem to work. Any help would be greatly appreciated. Thanks.

  15. [...] , download patched Inventures_Olk.dll from here and patched Lookout.dll from here.I followed Mike’s instructions in different places, to make it done. IMPORTANT: TRY NOW IF ITS WORKING, IF NO [...]

  16. Thanks, yair – your method worked for me with Outlook 2007 on Win 7 64 – your “if not” hint was necessary. However, Outlook crashed during indexing. I “fixed” this by removing my archive folders from the index list and the indexing ran to completion.

  17. leo.graper says:

    Just installed 1.30 on my XP SP3 rig, no hassle what so ever, works like a charm!
    No renaming, deleting, cleaning, 200Mb PST, indexed within 2 minutes…

  18. Jim says:

    I am able to successfully install and run Lookout on Outlook 2007, Windows 7 x32 system. Occasionally I notice that my Index file doesn’t automatically update; I do a search and find no results for some recent period of time. I am able to successfully “rebuild index from scratch” when this occurs, but I’d like to avoid doing so.

    I have my preferences set to add items every 60 minutes and rebuild from scratch in the background every 7 days.

    Any suggestions on this one?

    thanks in advance for any help!

  19. I’ve just got it running with x64 Windows7 and Outlook2007.

    Short version:
    * Install 1.30
    * Start cmd as admin and do the renaming of Microsoft.Office.Interop.Outlook
    * Start outlook
    * Disable Outlook search (search options, “down-arrow” next to magnifying glass in outlook)
    * Lookout -> Options -> Advanced. Decrease Indexer Aggressiveness. (test until it works to index without crash)
    * Index (repeat previous)

    That’s it.

  20. I’m using Win7 32-bit and Microsoft 2010 32-bit with Exchange

    Using lookout 1.2 and test & index successfully

    Preinstallation step
    1) start > run Cmd run as administraor
    2) type cd %systemroot%\assembly\GAC_MSIL
    3) type rename Microsoft.Office.Interop.Outlook Microsoft.Office.Interop.Outlook.old
    4) type nul > Microsoft.Office.Interop.Outlook
    5) type rename Policy.12.0.Microsoft.Office.Interop.Outlook Policy.12.0.Microsoft.Office.Interop.Outlook.old

    Installation Steps
    1) Go to Windows Explorer and create a new directory for installation of lookout 1.2. for e.g C:\Program Files App\”
    2) Install lookout 1.2 to the new directory for e.g C:\Program Files App\”
    3) Start outlook

    I try lookout 1.3 and replace with customised Inventures_Olk.dll & lookout.dll but does not work

    Happy Installing

  21. Haider says:

    - Ok here is my issue i have tried all what i could do
    - Windows 7
    - Office 2007
    - Empty RSS
    - Empty Deleted
    - Disable Outlook Search ( not sure if i need to do more ) Screen shot included
    - Rebooted my pc
    (All settings are in below link Screen shots included )

    Still have i have as i stared Indexer even selecting a folder with single email .
    my email closed and crashed .
    Please SOS help ASAP kind Regards

  22. Haider says:

    (00.07s) Info: ***** 10/20/2012 5:17:02 AM Lookout Outlook (loglevel=Debug) [Chrome.AddIn.OpenLog()]
    (00.01s) Debug: user name is myname, smtp address is [Chrome.AddIn.StartChrome()]
    (00.03s) Debug: Creating IndexerNotifyForm [Chrome.AddIn.StartChrome()]
    (00.15s) Debug: attempting paste of pre-ol2003 commandbar button bitmap size={Width=16, Height=16}, pixelformat=Format32bppRgb [Inventures_Olk.AddIns.CommandBarButton.SetFaceIconPreOutlook2003()]
    (01.97s) Info: clicked ‘Indexer’ button [Chrome.UI.ChromeButton.OnClick()]
    (04.67s) Info: clicked ‘Options’ button [Chrome.UI.ChromeButton.OnClick()]
    (51.21s) Info: clicked ‘Indexer’ button [Chrome.UI.ChromeButton.OnClick()]
    (01.82s) Debug: Clicked Start, rebuild=False [Chrome.UI.IndexerForm.buttonStartStop_Click()]
    (00.00s) Debug: Indexer Start() rebuild=False, prior state=Idle [Chrome.Indexing.Indexer.Start()]
    (00.05s) Debug: Indexer thread starting on 10/20/2012 5:18:02 AM [Chrome.Indexing.Worker.IndexStart()]
    (01.66s) Error: Downloaded upgrade manifest file with invalid signature [Chrome.UI.SysTray.Updater_CheckNewSoftware()]

    - if i chose my documents indexer works fine without any issue
    - If i chose empty folder in Outlook it works fine no error
    - i tried best to reduce the emails from my inbox
    - as son i select email folder even i has single email and start indexer
    - it crashed outlook and (Outlook Not responding ) i have to close (Kill process ) and restart Outlook

    i have included logs above from log file and used every possible settings inoutlook and included screen shots

    I hope someone can help me on this page

  23. Haider says:

    - Ok Finally hours of working i got this working :) .
    - Here is what i have done .
    - I Repaired Office using add /remove programs
    - Rebooted my system
    - uninstalled lookout
    - Rebooted system
    - make sure i have no pst attached / no public folder / no RSS / empty deleted folder / empty drafts /
    - make sure outlook search option disabled ( explained above )
    - followed below commands in CMD
    - cd %SYSTEMROOT%\assembly\GAC
    - rename Microsoft.Office.Interop.Outlook Microsoft.Office.Interop.Outlook.OLD
    - rebooted system
    - now installed lookout
    - all Done happy no further issues indexing is running perfectly
    now i have attached my pst which is also working fine.

    many thanks . for this tools ;) .

  24. dreed says:

    I have tried the above steps…
    install 1.3, rename the Interop.outlook file, start outlook… and still no luck getting Lookout to work. I get the same “polite” but aggravating message every time I start outlook. I even tried disabling my outlook search and emptying my deleted items folder. I’ve been using Lookout successfully with Windows XP and Outlook 2007, but just got upgraded to a new PC running Windows 7 and Outlook 2007. Any suggestions?

  25. Tom Leen says:

    Unfortunately this did not work for me and when I tried to go backwards as stated above by renaming the file
    I got the error message ‘A duplicate filename exists, or the file cannot be found’
    Can anyone help me out please?? Outlook just crashes now and I cant open it!!!


  26. Richard O'Neill says:

    Can anyone advise a solution to get Lookout working on Windows 7 & Outlook 2010 ??

  27. 郭磊 says:

    For WIN7 & Outlook 2010:
    according to my tests: Lookout 1.2 will work with Outlook 2007, while Lookout 1.3 will work with Outlook 2010.
    follow the steps below:
    besides, a good summary:

  28. Below link worked for me on Win XP and Win 7 and OL2007.
    Just a note that it worked only after .Net Framework 2.0 was installed on all machines

    Thanx Mike and Vlad

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