How to open .OTC files on iOS
To open .OTC files on iOS, iOS typically won’t handle .otc chart templates well in the built-in viewer; transfer the file to a desktop office suite that supports OpenDocument chart templates.
Step-by-step instructions
- iOS typically won’t handle .otc chart templates well in the built-in viewer; transfer the file to a desktop office suite that supports OpenDocument chart templates.
Common issues
“Windows can’t open this file” / no app is associated
Your system doesn’t have an OpenDocument-compatible office suite installed, or the .otc association is missing.
- Install an office suite with OpenDocument (ODF) support.
- Use “Open with…” to select that suite and set it as the default for .otc files.
The file opens, but appears blank or not as expected
An .otc is a chart template, not a finished chart document—some apps may only apply it when creating/editing a chart.
- Try opening it from within the office suite’s chart workflow (for example, when selecting a chart template).
- If your suite has limited template support, test with another OpenDocument-compatible suite/version.
File type looks wrong on Linux (opens in the wrong app)
Your desktop’s MIME database or file association may not be updated, so the .otc extension isn’t mapped correctly.
- Update your desktop’s MIME database and file associations (shared-mime-info is commonly used for this on Linux).
- Manually set the default application for application/vnd.oasis.opendocument.chart-template to your office suite.
Security note
.otc is an OpenDocument package type; treat it like any complex document format—only open files you trust because malformed documents can exploit parser bugs in document software.