How to open a .OO3 file online
No extra software to download or install.
Pick your .OO3 file
Drag it in or click to choose it. We read its contents list first, so it opens right away without unpacking everything.
Browse what's inside
See every file with its size, how much it's compressed and its date, and search by name across all the folders.
Preview or download
Click a file to preview text or images, or save just that one. Need everything? Download it all as a single ZIP.
About .OO3 files
What a .OO3 file is, and what's inside it.
An .OO3 file is a document created by The Omni Group for use with OmniOutliner 3. These data files typically contain structured outlines, including text and hierarchical data. They are opened and managed using Omni Group Outliner software.
Programs that open .OO3 files
| Developer | The Omni Group |
|---|
Related viewers
Found something inside the archive? Open it here.
Do I have to unpack the whole .OO3 file?
No. The viewer reads its table of contents first and only unpacks a file when you click it. That works even with multi-gigabyte archives, because we read just the bytes we need.
Can I open password-protected archives?
Yes, for ZIP (ZipCrypto and AES) and 7Z. You'll be asked for the password,. We can't recover forgotten passwords.
Is my .OO3 file uploaded anywhere?
No. The code that unpacks the file is downloaded once and then reused.
Why does a .docx or .apk open as an archive?
Because they are ZIP archives under the hood. Office documents, Android apps, Java programs and EPUB books all use ZIP as their container.
What about split archives (.001, .z01, .part1.rar)?
Multi-part archives need all their parts. Today you can open the first part to see the file list; joining parts is on our roadmap.
Was this tool helpful?
Your rating helps us decide which tools to improve next.