How to Open MD Files on Mac

An .md file is a plain-text markdown document — the format behind READMEs, documentation, and notes exported from Obsidian, Notion, ChatGPT, or Claude. macOS has no built-in app that renders it, so double-clicking one usually lands you in Xcode or TextEdit staring at raw # symbols. Here are the three ways to actually read it.

The three ways, compared

Method	Rendered output?	Best for
Quick Look / TextEdit built into macOS	No — raw markdown text with visible `#` and `*` symbols	A quick glance when formatting doesn't matter
Code editor with preview VS Code, JetBrains, …	Yes, in a side preview pane	Developers already working inside an IDE
Dedicated markdown viewer MarkViewer, free	Yes — full GitHub-flavored rendering, instantly on double-click	Reading and light editing of any .md file, offline

Online markdown previewers are a fourth option, but they require uploading your file to someone else's server — a non-starter for private notes or work documents. Everything below runs locally on your Mac.

Open an .md file rendered, in three steps

Install a markdown viewer. Download MarkViewer, a free markdown viewer for Mac — it's a signed, notarized universal binary for Apple Silicon and Intel (macOS 10.13+). Open the DMG and drag MarkViewer.app into Applications.
Double-click the .md file. The document opens rendered — headings, tables, task lists, fenced code blocks with syntax highlighting, even Mermaid diagrams — the same way GitHub renders it. You can also drag the file onto the dock icon or press ⌘O inside the app.
(Optional) Make it the default for every .md file. Right-click any markdown file in Finder → Get Info → Open With → choose MarkViewer → Change All…. From then on, every .md file from Finder, Spotlight, AirDrop, or your downloads folder opens rendered.

Tip: MarkViewer's first-launch setup offers to register itself as the default app for .md files — one checkbox instead of the Finder Get Info dance.

Fix: .md files keep opening in Xcode or TextEdit

macOS hands .md files to whichever installed app last claimed the extension — for developers that's usually Xcode, which takes several seconds to launch just to show plain text. The fix takes ten seconds:

Right-click any .md file in Finder and choose Get Info.

Expand the Open With section and pick the app you want.

Click Change All… and confirm. Done — the setting applies to every markdown file on your Mac.

Common Questions

What app opens MD files on a Mac?

Any text editor can open an .md file, but it will show raw markdown syntax. To see the formatted document — headings, tables, task lists, code blocks — use a markdown viewer such as MarkViewer, which is free, native to macOS, and works fully offline.

Can I open an MD file without installing anything?

Yes. Press Space on the file in Finder (Quick Look) or open it in TextEdit — both show the file's text, but as raw markdown with visible # and * symbols, not the rendered document. Online previewers render it but require uploading your file to a website.

Why does my .md file open in Xcode or TextEdit?

macOS assigns .md files to whichever installed app last claimed the file type. To change it: right-click the file in Finder, choose Get Info, expand Open With, pick the app you want, and click Change All to apply it to every markdown file.

Is an MD file safe to open?

Yes. An .md file is plain text with markdown formatting symbols — it contains no executable code. It's the standard format for README files, documentation, and notes exported from apps like Obsidian, Notion, or AI chat tools.

How do I open markdown files from ChatGPT or Claude?

Save or export the AI-generated content as a .md file, then open it in a markdown viewer. MarkViewer renders it exactly as the chat interface did — and its AI Review Loop lets you annotate the draft and hand it back to the AI for another pass.

Open your first .md file in under a minute

MarkViewer is free, fully offline, and renders GitHub-flavored markdown natively on macOS 10.13+.

Download for Mac (Free)

Universal Binary (Intel & Apple Silicon)