Osmo – Free Light Contact Management & Calendar Software

Karl L. Gechlik 18-12-2009

oHeadDo you hate using Microsoft products? Do you instead want to use a free, lightweight, easy to use calendar and contact management application?


Well I needed something very lightweight for a project I was working on. My requirements were to use a small amount of memory, be cross-platform, we needed a calendar, Tasks, Contacts, Notes. Last of all, it needed to be easy and intuitive.

I went looking and I found a little application quickly called Osmo on Sourceforge. It fit the bill to a tee. You can find the project’s page over at this link here and the authors home page is over here.

The Windows download for this free contact management software is a measly little 4.6MB. The application is available for Windows or Linux and is released under the GNU General Public License.

After a easy installation of next, next, next you will see this screen:



On the calendar screen we have an easy to use calendar which display the current time, day of the year, amount of days till the year is over, week number, the amount of days you have marked as well as the moon phase. Click on one of the days and enter notes in the text box like so.


You can click on the timeline icon at the bottom of the screen where you can insert a timeline. I chose 8 hours in 1 hour intervals and I now see this:



You can fill in your information as needed. It is not Outlook but then again Outlook running at under 7MB of memory at its peak would never happen. No matter how hard you try you will always be closer to 100MB of memory than 10MB like Osmo. You can change the color of days on the calendar so you can tell what’s what from a quick glance.

Next up is the tasks tab. Here you can set up your to-do lists or other tasks and you can create categories and filter by them. They get a due date and a summary.


After you hit the add new task button you will see this screen where you can fill in the information. There is a check box to enable a sound notification when the task has come due. It won’t light up unless you change the no due date box. You can also choose priorities including high, medium and low. Nothing revolutionary but very lean and awesome.



The next tab is your contacts – you can’t have free contact management software without the contacts right?




There is a show birthdays button that will show you all the birthdays at a glance for easy reference. The button looks like a present up there in the task bar.

The notes tab gives you a place to…um…write and read notes. Big shocker!  Then we have our options. We all love our options right? You can choose your fonts, color highlighting and more for each tab independently.

And did I tell you it runs at less than 7 MB of memory but it also runs on slow as molasses machines?  So I was able to equip 10 machines over 10 years old with Windows 2000 Pro on them to run this for a small charity organization. It turned out well!

Do you have other lightweight, free contact management software alternatives for bogged down commercial solutions? Post them in the comments!

Related topics: Calendar, Contact Management, Planning Tool, Task Management.

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  1. Ashlan Bardell
    July 10, 2019 at 3:33 am
  2. ninja
    January 6, 2010 at 12:40 am

    It seems that the maintainer of this software quit support windows. He or she removed the installation file from sourceforge.

  3. eric
    December 27, 2009 at 12:02 am

    May I know how to locate the .exe file? I am sorry for the naive but I dont know how to install this software.

    • ska
      December 28, 2009 at 6:29 am

      You can download Universal Extractor here:

      Then, right-click the setup file to extract. I usually choose "UniExtract Files..." and choose which folder to extract to. UE extracts the file like you would extract a zip file. Then find the exe file in the folder or subfolder you extracted.

      Hope this answers your question. Merry festive season! :o)

  4. ska
    December 24, 2009 at 7:29 am

    You can download Universal Extractor and open the setup file using UE. It will open it like a zip file and then you can run it from the osmo.exe file. It works on win xp. Haven't tried running it on different computers yet (to check data portability) but if it saves the info in the same folder it should be portable.

    One question: The interface is a bit too large and bulky (seems like a program from the 640x480 days) ... Any idea if/how this can be adjusted?

  5. Doug
    December 20, 2009 at 2:12 pm

    Any indication of this replacing Outlook as the PIM for a Blackberry?

    I've looked at the links, and don't see anything that would show this, but just having an alternative to any paid product is great in itself.

    Another good find care of MUO!

  6. Node Tech Blog
    December 19, 2009 at 3:58 pm

    These apps can somtimes be hard to come by, good to know its for free.

  7. The Bobster
    December 18, 2009 at 8:32 pm

    When I try to install it for Windows 7 every extract file generates an error and it won't install.

  8. Dennis
    December 18, 2009 at 10:09 am

    This is a nice alternative to the bulky microsoft outlook. I would like a cloud storage contact manager though. Does anyone know of a good one?

  9. BigWaveDave
    December 18, 2009 at 8:35 am

    Beautiful piece of software, but is it portable or can it made that way? I keep my life on a USB drive and would love to use Osmo.