ODIR is an add-on for Outlook that can detect duplicate items and move them to a special folder; these include contacts, appointements, tasks, notes, and emails (sent, received, and unsent). Does not work with Outlook Express.

I used this program with Outlook 2007 to scan around 18,000 emails for duplicates.

Of these, approximately 10,000 were duplicates (after migrating my email from Thunderbird to Outlook, I somehow created 2 copies of 5,000 of my emails).

Here are some notes on my experience with this program:

  • Running the program: the installer creates an ODIR menu alongside Outlook’s original menus. Deduping begins when you select ’Remove Duplicate Items’ from this menu.
  • How it works: items are considered duplicates if the following criteria are found duplicated: for contacts: first and last names, company name, and email address; for appointments: subject, location, start date, and end date; for tasks: subject, start date, due date and status; for notes: contents of the body and color; for emails/posts: internet message ID (for received email), email subject and the time sent (for sent email), and the subject alone for unsent emails.
  • Effectiveness: it took about 4 hours for ODIR to sift through 18,000 emails. It was a processor-intensive affair and at times I found myself wishing that there was a pause button or even a mere indication that it was still chugging along and not crashed (the progress gauge was moving very slowly). No sooner than it was done, after about 4 hours, that it crashed. Fortunately it had already moved all duplicate emails into the ODIR_duplicate_items subfolder, and I was able to delete those. I speculated as to whether the crash was due to an incompatibility issue with Outlook 2007. In any case, the job was done.

I searched for a very long time for a free program that can detect duplicate emails in Outlook and I am very grateful that I found this one. In the end it did a very fine job.

Version tested: 1.2.1

Compatibility: A Windows machine that runs Outlook. Does not work with Outlook Express.

Go to the program page to get the latest version (approx 1.87 megs).

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Has been reviewing software since 2006 when he started Freewaregenius.com
  • Brian

    Any recommended programs to detect duplicate files on a hard drive?

  • I’ve been using Outlook Duplicates Remover (written by an ex-programmer / priest) for a couple years. It still works perfectly well with Outlook 2007, and it’s been quite stable.

    It’s hard to find, but you can download it from a French site at http://objs.net/ODRsetup.exe

  • Salty

    RE: Brian on May 26th, 2007 Any recommended programs to detect duplicate files on a hard drive?

    My favorite is double killer:

  • Makson

    Any recommended programs to detect duplicate files in Outlook Express?

  • Makson

    Great site man keep up the good work
    Can you recommend a synchronization utility for Outlook & Outlook Express to be used on two or more different machines.

  • Anonymous

    I could not find it work on my Outlook 2007 12.0.6023.5000 MSO 12.0.6017.5000 hungarian 🙁
    Nothing has put into the menu of Outlook

  • Mark F.

    Brian: Look for DoubleKiller by Big Bang. It’s a tiny program, it works incredibly well (I’ve used it to delete tens of thousands of duplicates and I’ve never seen it make a mistake), it sorts really fast, and it’s free. Just be aware that the free version does NOT delete to the Recycle Bin, so if you’re not sure about a file, you should use the program’s Move option instead of deleting.

  • Mark F.

    Oops, just realized that someone already recommended DoubleKiller. Well, I second the rec. It’s one of my two favorite tiny utilities (the other is Cathy by R. Vasicek).

    Also thanks to Cristos for posting the link. I’ve been looking for that app. I like it better than ODIR.

  • Mark F.

    Alright, the app Cristos posted the link to wasn’t the one I was looking for. The one I like is Anti-Dupe for Outlook. Unfortunately, it’s no longer freeware, but I found an old copy. Worth looking around for it.

  • Kent

    Doublekiller is a file dup, not an mail dup so cannot compare with ODIR.

    Outlook Duplicate Remover at http://objs.net/ODRsetup.exe is a hidious thing. It doesn’t use indexing and compares each file with each other one. Fine if you only have a few to check but if you have 10,000, you’re looking at 100,000,000 file compares and weeks of processing.

    We can see why he is “ex-programmer” 🙂

  • enter8

    I installed ODIR on two rigs:

    1. XP SP2 Outlook 2003
    2. XP SP2 Outlook 2000

    On the 2003 machine I get an error when Outlook loads at startup:

    “object variable or with block variable not set

    errorin clsContactInsp.CreateSharingMenu”

    Which results in no ODIR on the menu. If I restart Outlook, ODIR appears.

    On the 2000 rig, I installed ODIR, used it once to delete about 50 dupes, went back the next day and it’s gone from the menu completely- even with a re-start.

    This is incredibly frustrating. It worked well once and I desperately need the functionality, but I can’t get the menu item back.

    If anyone can offer any ideas, I’d appreciate it.

  • Attila Medve

    Dear enter8!

    “object variable or with block variable not set

    errorin clsContactInsp.CreateSharingMenu”

    Did you manage to solve the problem? What is the solution? Please help me!

    Thanks in advance, Attila

  • Ruth

    I can’t get ODIR to work on Outlook 2007. I have installed it (and uninstalled) TWICE. The ODIR option does not appear on the File menu.

  • Pat

    I have to keep installing ODIR to use a 2nd or 3rd time. the icon disappears in my outlook 2007. Also when I have removed the program I get a ‘code 5’ when I try to reload the program again.

    Please help before I go and purchase another program that doesn’t create this kind of grief for me.

    • Samer

      @ Pat: I’m afraid I cannot think of another Outlook deduper at the moment. ODIR worked fine under Outlook 2003 but apparently not so under 2007+. Sorry!

  • Andrew S.

    @Pat: I know this comment is a little late to the game but I had the same problem that Pat was having and fixed the issue by first ensuring that UAC (User Account Control) was turned off and also make the user a local admin on the computer. Once I did that I installed again and it worked!

    Windows 7 64 bit, Office 2007 32 bit

  • just realized that someone already recommended DoubleKiller. Well, I second the rec. It’s one of my two favorite tiny utilities (the other is Cathy by R. Vasicek).

  • Sara

    Awesome Andrew, it worked – a million thanks!

  • ef

    @Andrew: Thank you! It worked like a charm! I think the creators of ODIR should also include this in the instructions on their website.

  • Hylton

    Has anyone had jot in making this product work with outlook 2010? I get the ODIR menu option but it gives an error reding the folder sructure. “ODIR was unable to read your PST file or OST file. Removing duplicates are not possible”


  • mh

    @Andrew: Thank you! It worked like a charm for me too! I think the creators of ODIR should also include this in the instructions on their website. Saved me a bunch of $.

  • Ronski

    I’ve just also installed this in XP with Outlook 2007 exchange and could not get it to show up.

    This method solved the problem.

    On the tools menu click Trust Center, then click add-ins

    Look at the list, mine showed ODIR as disabled

    If this is the case, at the bottom next to Manage, select Disabled Add-in’s from the drop down and click go.

    Now select ODIR and click enable, then restart Outlook, and you should now have a new menu item.

    I would suggest doing one subfolder at a time, as it seems as slow as other’s suggest, but at least it works.

  • SafeBoy

    @Andrew … thank you … I was going around in circles … ODIR is one of the best little programs around … and it baffles me how it got disabled … but, it is back and removing things as I type 🙂

  • SafeBoy

    Addendum –
    * remove ODIR if already installed (close outlook first!, check running tasks to make sure)
    * Turn the UAC down to OFF – tells you you have to reboot, (wait until after the next step)
    * ensure user is {local} admin – ie Administrator – why “local” is used no clue.
    * reboot PC
    * install ODIR
    * open Outlook
    Should all just work … 🙂

    **system is Win7 Ult, 64bit, Office Ultimate 32 bit, 16gb ram etc …

  • howard weatherly

    I have been looking for an answer to this question: (What does ODIR do with the original?) Is the original simply considered a dup or does ODIR realize that it is not on a mission to delete the single original? Anyone?

  • Mark