Open .txt files in CotEditor by default on Mac

Method 1: Use Finder

1. In Finder, select a sample file such as draft.txt.
2. Press Command–I, or choose File → Get Info.
3. Expand Open with and choose CotEditor. If it is missing, choose Other and locate the installed app.
4. Click Change All and confirm the macOS prompt.
5. Double-click another file of the same type to check the new default.

Method 2: Manage associations with Pahkui

Pahkui lets you browse by app or by format. When setting up an editor for several file types, you can inspect the current defaults and review pending changes in one window. Requires macOS 14 or later.

1. Open Pahkui, switch to Format, and search for the extension you need from .txt.
2. Select CotEditor. Use Choose another app if it is not listed.
3. Review the pending association, click Apply changes, and confirm the new app in the macOS dialog.

The formats in this guide can be configured with Pahkui Free. The manual Finder method does not require a purchase. See pricing

If the default app does not change

• Changing .txt does not change .rtf. Choose a rich-text capable app for documents that need formatting.
• If line endings or encoding look wrong, adjust those options in CotEditor before saving a copy.
• If CotEditor is missing, confirm it is installed and can open the sample directly, then locate it with Other. If an extension is absent from the catalog, add the format in Pahkui. Changing an association does not add format support to the target app.

Common questions