OmniOutliner 2 OS X Files


Warm greetings to you from Scotland. I am very much hoping you can help me.

I have 82 files full of notes in the OmniOutliner 2 (OS X) dating back to 2003 and 2004. I have upgraded OmniOutliner over the years and currently have OmniOutliner 5 but now, going back to open my old notes,

I see the error message:

“OmniOutliner no longer supports reading OmniOutliner 2 files”

I am unable to install an old version of OmniOutliner 3 (I have High Sierra OS), which I had hoped would give me access to all my painstakingly created note files.

  1. Is there anything I can do to easily open and/or convert these 80 some .ooutline files?

  2. Should I be doing something to the 672 files full of notes in the (I assume OmniOutliner 3) .oo3 format in order to get them into the most recent Omni file format (or exported into to rtf or something else that will be stable in the long term?


Konrad M. Lawson


You have come across the unfortunate circumstance of having files that are so old that they (generally) can no longer be accessed. In my experience, this phenomenon is more prevalent in early versions of software as the developers are still garnering their footing. As you have come to find out, while OmniOutliner 5 can open and convert documents in the OmniOutlier 3 format (.oo3) that was used through OmniOutliner 4, it does not support earlier OmniOutliner formats.

Fortunately, you can go here to download previous versions of OmniOutliner, as well as any other Omni Group product. Hopefully, OmniOutliner 3.10.6 will have the ability to open and convert older OmniOutliner documents; it stands to reason that it should. The one thing that seems to be missing is information on the licensing for the older applications. That being the case, I would guess the the downloads on that page are fully functional without the need for a license key or some method of acquiring a license key will be provided.


Continuing the discussion from OmniOutliner 2 OS X Files:

Thanks so much for your reply. Alas, those older versions of OmniOutliner won’t open on newer versions of OS X. I don’t suppost you have any other suggestions?




It looks like you need access to a Mac running a system older than 10.12 Sierra to be able to start Omnioutliner 3 (Omni apps on MacOS Sierra), which should be able to open Omnioutliner 2 files, so that you may convert them to the .oo3 format and then open them in Omnioutliner 5

To convert your Omnioutliner 3 documents to the most recent Omni file format, open the files in Omnioutliner 5 and click on the button Convert at the top of the document.

I’ve had problems resembling yours especially with old Word files and decided that the rtf format for me is a much safer and more convenient file format in the long term, as long as its formatting capabilities works well enough for my purposes. In most cases I’m happy just being able to read the contents of the documents, and then rtf works great. Formatting is also handled surprisingly well. If you need Omnioutliner-specific features, I would recommend you to routinely update your files to the latest file format. Old file formats tend to cause problems sooner or later, and the older the file formats, the more complicated and frustrating it becomes to get the files readable again.


I would mostly agree with Jan_H.

The rich text file format (RTF) is suitable for documents that are text-based and that do not have demanding formatting or layout requirements. RTF files can be opened in just about any text editor or word processor. Of course, if you are using OmniOutliner, then your requirements are very likely beyond what can be done with a rich text document.

If you are creating a simple static outline, OmniOutliner may be overkill. OmniOutliner’s strength is in the fact that it has long surpassed being a on trick pony. I do not know how OmniOutlier was prior to v3, but it would not surprise me if v1 was not much more than a simple outliner. Today, OmniOutliner is powerful structural document generator that includes true parent-child relationships upon which its feature set is built; rich text applications do not have this capability.

The same is true of Microsoft Word in that it is overkill for composing simple text documents. Most people perhaps rarely use TextEdit (macOS) or Wordpad (Windows), but those simple word processors are excellent tools for creating simple text documentation.

Proprietary file types have a tendency to dramatically change over time, so a simple rule of thumb for any software is to keep your files up-to-date. Of course, that type of task can be quite time consuming and few applications have a batch conversation process.

The real irony for OmniOutliner users is the fact that OmniOutliner is the only outlining software that supports OPML; think of it as the RTF equivalent for hierarchal documents. So, we can save a copy of our .ooutline documents as an OPML file, but to date, OmniOutliner is the only outliner software that can open OPML files. The entire purpose of the OPML format is to permit transporting outlining documents between applications, but outside of its use on the Web—if you look up OPML you will see more about RSS feeds than anything associated with outlining software—it is slim pickings. That is very unfortunate.